|
BFNA Title: Hygrohypnum |
|
XX. HYGROHYPNUM Lindberg, Act. Soc. Sc. Fenn. 10:
277. 1872 * [Greek hygros, wet or
moist, and Hypnum, alluding to the hygric
habitat] David
W. Jamieson Calliergon
subg. Limnobium Kindberg;
Calliergon subg. Pseudo-Limnobium Kindberg; Calliergon sect. Molliformia Kindberg; Calliergon
sect. Montaniformia Kindberg; Calliergon sect. Ochraceiforme Kindberg; Hygrohypnella
Ignatov & Ignatova; Hypnum subg.
Limnobium (Bruch, Schimper &
Gümbel) Sullivant; Ochyraea Váňa; Pseudohygrohypnum Kanda Plants
small to robust. Stems
usually 1--15 cm, irregularly branched, in section cortex of several layers
of darkly pigmented, thick-walled cells, rarely with ill- to well-defined
hyalodermis with hyalodermis or a layer of cells with a thinner outer
tangential wall, central strand well-developed, rarely poorly so, or absent. Leaves ovate to broadly-ovate, oval,
orbicular, ovate-to oblong-lanceolate to lanceolate, straight or
falcate-secund or both, apex broadly rounded or obtuse to acute, occasionally
apiculate from an obtuse or rounded apex, sometimes blunt from an acute apex,
usually shallowly to deeply concave, rarely plane; margins entire or weakly
denticulate or serrulate, usually plane, sometimes recurved in the apex; costa
usually short and double and ending before mid-leaf, occasionally long and
double, often single and slender or stout, reaching 1/2--3/4\x leaf length,
rarely percurrent; laminal cells medially largely linear-flexuose, sometimes
short-rhombic or fusiform, marginally short or very long; alar cells
undifferentiated or little differentiated from adjacent cells or variously
forming small and irregular to large groups of quadrate, short-rectangular or
irregular cells or groups of enlarged and thin-walled to inflated cells,
plane or excavated, hyaline, yellow-brown, brown, reddish brown, rarely
bright red. Sexual condition
autoicous or dioicous; inner perichaetial leaves erect, plane, or nearly so;
costa absent, short and double, long and double or single and/or forked;
margins plane, rarely recurved, entire or coarsely serrulate, especially at
the apex, apex obtusely-acute or long, tapering-acute, medial cells smooth,
rarely with a few subapical cells abaxially papillose by distally
over-lapping end-walls. Capsule ovoid
to oblong-cylindric, erect, symmetrical or inclined, slightly to strongly
arcuate; operculum conic or conic-apiculate; peristome double, endostome of 1--3
rudimentary to well-developed cilia. Species 16 (16 in the flora); widely distributed in the montane,
boreal and arctic North Temperate Zone, usually on irrigated rocks or stones
in or beside cold, swift mountain streams, occasionally on seepy sites. The genus Hygrohypnum
has long been understood to be taxonomically difficult. As circumscribed here,
it remains a repository for a number of coherent and disparate elements. Of
late, there are few helpful cladistic and molecular analyses (Ignatov, M. S.
et al. 2007; Kanda, H. et al. 2004, 2006; Oliván, G. et al. 2007).
These studies seem to expose just as many uncertainties, if not
contradictions, as they give insight. Most troubling, the molecular
investigations ignore profound morphological issues. The genus requires further study. Difficulties in identification are various. There is variability
in leaf shape within a single specimen.
Descriptive terms for leaf shape are imprecisely applied. Failure to
remove intact leaves during dissection is problematic. Careful observation of
alar cells in intact leaves is absolutely necessary. A pair of sharp, very
finely pointed dissecting needles is essential. Fully formed, mature leaves should be
stripped from the stem or branch one at a time, under magnification, to see the
leaf insertion and tease the leaf away intact. Alar cells in immature leaves
are incompletely developed and shape, wall thickness, wall color, and
differentiation are regularly obscured by cytoplasmic contents. It is strongly recommended that leaves
selected for examination be first cleared with a clearing agent such as lacto-phenol
or, better, with Hoyer’s solution. SELECTED REFERENCES: Ignatov, M. S. and E. A. Ignatov.
2004. Moss Flora of the Middle European 1. Stem section
with hyalodermis or at least some cells have a slightly thinner and less
pigmented outer tangential cell wall compared with the other epidermal cell
walls and the sub-adjacent cortical cells. 2. Costa uniformly strong and single, percurrent
. . .13. Hygrohypnum polare 2. Costa short and double, or double to
mid-leaf, or if single or forking, then ending well before the apex. 3. Alar cells inflated, forming a distinct
group of cells, often becoming red or reddish brown with age; leaf apex acute
. . .7.Hygrohypnum eugyrium 3. Alar cells wider and shorter than
adjacent cells, but neither inflated nor abruptly different, marginal alar
cells increasing in length distally from the point of insertion, hyaline or
yellowish, never red; leaf apex blunt . . .12. Hygrohypnum ochraceum 1. Stem section
with epidermis of small thick-walled cells similar to the sub-adjacent
cortical cells. 4.
Leaves falcate-secund or some leaves on the same or different stems
within the same specimen falcate-secund or straight. 5. Leaves exclusively falcate. 6. Alar cells undifferentiated from
adjacent cells. 7. Leaf margins finely to coarsely
serrulate, especially in apex, narrowly recurved, particularly in the proximal
half of leaf . . . .10. Hygrohypnum
montanum 7. Leaf margins always entire and plane .
. . . 13. Hygrohypnum styriacum (in
part) 6. Alar cells well differentiated; small,
numerous, quadrate to short-rectangular, incrassate or inflated; plane or
excavate. 8. Alar cells inflated . . .7. Hygrohypnum eugyrium 8. Alar cells small, quadrate to short-rectangular,
incrassate. 9. Leaf apex always acute, margins entire .
. . . 8. Hygrohypnum luridum 9. Some leaf apices obtuse and margins distinctly
denticulate, or acute with a few fine teeth . . . .16. Hygrohypnum subeugyrium 5. Falcate-secund and straight leaves
occurring simultaneously on the same stem or on different stems in the same
specimen. 10. Leaf apices always entire. 11. Leaf apex acute; alar cells numerous,
quadrate to short-rectangular; annulus absent . . . .8. Hygrohypnum luridum 11. Leaf apex abruptly acuminate; alar cells
undifferentiated or of a few quadrate cells; annulus present; . .
.15. Hygrohypnum styriacum (in
part) 10. Leaf apices bearing a few fine teeth. 12. Alar cells inflated, thin-walled, leaf
apex always acute; stem epidermis differentiated as an ill-defined
hyalodermis . . .7. Hygrohypnum
eugyrium 12. Alar cells quadrate to slightly
enlarged, incrassate; some leaf apices obtuse and denticulate; stem epidermis
similar to cortical stem cells . . .16.
Hygrohypnum subeugyrium 4. Leaves all straight, sometimes secund. 13. Leaves broadly ovate, oval to orbicular,
usually less than 1.5/x as long as wide. 14. Median marginal leaf cells 60 \um or
longer…3. Hygrohypnum bestii 14. Median marginal leaf cells rarely longer
than 55 \um. 15. Alar cells clearly differentiated,
either thin-walled or incrassate. 16. Alar cells thin-walled, usually hyaline,
enlarged, rounded-rectangular, forming a rectangular group whose long axis
parallels the leaf margins; leaves mostly broadly ovate to orbicular; inner perichaetial leaves papillose on the
abaxial surface near the apex . . .2. Hygrohypnum
alpinum 16. Alar cells incrassate, clearly pigmented
in older leaves, quadrate, short-rectangular or irregular, forming an
irregular group; leaves mostly broadly ovate to oval; inner perichaetial
leaves smooth abaxially. . .6. Hygrohypnum
durisusculum 15. Alar cells undifferentiated or consisting
of a few quadrate to short-rectangular cells, thin-walled or incrassate. 17. Costa usually single and stout, reaching mid-leaf
or slightly beyond, sometimes forked or stout, short and double; plants very
coarse and rigid . . .14. Hygrohypnum
smithii 17. Costa almost exclusively short and
double, if single, then costa slender and plants soft. 18. Leaves deeply concave to cochleariform,
usually 0.8--1.2 mm, apex obtuse to broadly rounded; inner perichaetial leaf
margins entire and recurved; endostomial cilia 2--3 . . .5. Hygrohypnum cochlearifolium 18. Leaves concave, but never cochleariform,
usually 1--1.7 mm, apex tapering to bluntly acute point; inner perichaetial leaf margins coarsely
denticulate and plane; endostomial
cilia rudimentary or wanting . . .9. Hygrohypnum
molle 13. Leaves ovate, to oblong-ovate,
ovate-lanceolate to oblong-lanceolate, generally more than 1.5/x as long as
wide. 19. Alar cells clearly differentiated,
either inflated and mostly thin-walled or smaller, incrassate and quadrate to
short-rectangular. 20. Leaf apex narrowly recurved along the
margin and reflexed as a small apiculus, especially in leaves at or near the
stem or branch tips; leaves deeply concave, especially near the apex . . . 1.
Hygrohypnum alpestre 20. Margins of leaf apices plane or variously
inrolled, never recurved, apex never forming a reflexed apiculus. 21. Leaf apices always acute and entire . .
.8. Hygrohypnum luridum 21. Leaf apices acute with a few fine teeth
or obtuse and distinctly denticulate . . .16. Hygrohypnum subeugyrium 19. Alar cells undifferentiated or of a few
quadrate to short-rectangular cells not forming a recognizable group. 22. Leaf apex abruptly acuminate, tapering
to a slender tip; bracts surrounding perichaetia and perigonia. . . 15. Hygrohypnum styriacum (in part) 22.
Leaf apex obtuse or acute, with or without a blunt tip; perichaetia
and perigonia not in a bracted complex. 23. Costa predominantly single to mid-leaf or
beyond, sometimes short and double. 24. Leaf apex obtuse; plants coarse; inner
perichaetial leaves plicate, margins recurved. . . 14 Hygrohypnum smithii 24. Leaf apex acute with a blunt tip; plants
coarse, rather Amblystegium-like;
inner perichaetial leaves never plicate, margins plane . . . 4. Hygrohypnum closteri 23. Costa usually short and double, rarely
to mid-leaf or beyond. 25. Leaf apex entire; leaves usually 0.5--
0.8 mm . . . 11. Hygrohypnum norvegicum 25. Margins of the leaf apex uneven to
denticulate; leaves usually 1--1.7 mm . . . 9. Hygrohypnum molle 1.
Hygrohypnum alpestre (Hedwig)
Loeske, Verh. Bot. Ver. Brandenburg 46:198.
1905 Hypnum
alpestre Hedwig, Sp. Musc. Frond.,
247, plate 64, figs. 1--4. 1801: Calliergon alpestre (Hedwig) Kindberg;
Ochyraea alpestris (Hedwig) Ignatov
& Ignatova Plants
usually soft and in easily fragmenting patches, yellow or yellow-green with
or without rusty mottling above, older extremities dirty or reddish brown to
reddish black. Stems to 9 cm,
foliose throughout, often clogged with silt or denuded toward the base;
branching irregular; hyalodermis absent; central stand strong. Leaves
usually closely spaced and julaceous, sometimes spreading, generally little
changed from wet to dry condition; oblong to oblong-lanceolate, straight,
never falcate, (0.9--)1.4--1.6(--1.9) x (0.4--)0.6--0.7(--0.9) mm, deeply
concave, almost boat-shaped in the apex, generally tumid julaceous.; apex
acute to slightly obtuse becoming reflexed as a squarrose apiculus, though
eroded in older leaves; margins entire to uneven in the apex, narrowly
recurved especially in the distal 1/3 of the leaf and in the apex; costa long
and double with one arm reaching mid-leaf or single to the middle or beyond,
or short and double; basal cells becoming shorter, wider, and more incrassate
than medial cells; alar cells quadrate, short-rectangular to rectangular in a
well-defined group of thick-walled, enlarged, often discolored or excavated
cells; medial leaf cells uniformly long-linear-flexuose, (55--)65--90(--105)
\um, slightly longer in acute apices; apical and marginal cells generally
shorter. Sexual condition autoicous; inner perichaetial leaves
lanceolate to linear-lanceolate, costa absent, slender and single or double
to midleaf, plicate, margins entire or sometimes toothed toward the apex. Seta 7--16 mm, reddish brown. Peristome endostome with (2--)3,
finely, slightly appendiculate cilia. Irrigated, emergent acidic rocks in montane and northern
streams; moderate elevations, 700--1400 m; Greenland; B.C., Hygrohypnum
alpestre is most easily recognized by its narrowly recurved,
squarrose apiculus, which is best seen in stem and branch tips. Also
distinctive is the depth of the leaf concavity, with the leaf tip like that
of boat bow. The same concavity gives
the leaves a tumid-julaceous appearance on the stems or branches. Also, the alar region of quadrate,
short-rectangular to rectangular cells is well developed. 2.
Hygrohypnum alpinum (Lindberg) Loeske, Hedwigia 43: 194. 1904 Amblystegium
molle var. alpinum
Lindberg, Musci Scand., 33. 1879 Plants
usually soft when wet or dry, pale yellow, brownish yellow-green or bright
green. Stems to 5 cm, leafy throughout, branching irregular, ascending
to erect; hyalodermis absent; central strand hyaline to brownish. Leaves appressed-imbricate and plane or
erect-spreading and convoluted-ruffled parallel to the long axis of the leaf,
broadly ovate to usually oval or orbicular, (1--)1.2--1.6(--1.8) x (0.9--)1--1.7(--1.8)
mm; apex broadly acute to shortly apiculate, apiculus sometimes folded;
margins entire, less often finely denticulate or serrulate in the apex; costa
slender, usually short and double, sometimes single and forked; basal cells
shorter, longer or little changed from medial cells, usually thicker walled,
hyaline, alar cells enlarged to slightly inflated, irregular to rectangular,
often excavated, forming a more or less rectangular group, the long axis of
which is parallel to the alar margin, medial cells short-fusiform to
linear-flexuose, 35--60(--64) x (4--)5--6 \um, marginal cells little changed
from medial cells, apical cells shorter. Sexual
condition autoicous; inner perichaetial leaves linear-lanceolate to
linear, costa absent or faintly single or double, 0--4 deep plicae, apical
leaf margins coarsely serrate, apices with a few abaxial cells coarsely
papillose by distally over-riding end walls. Seta 8--20 mm, yellow-red, orange-red to red; Peristome endostomial cilia
rudimentary or absent. Irrigated emergent,
acidic rocks in montane streams; low to moderate elevations, 200--850 m ; B.C.;
Hygrohypnum
alpinum is disjunct from Europe to western 3.
Hygrohypnum bestii (Renauld & Bryhn) Holzinger, Bryologist 4: 12, plate 22. 1901 Hypnum
molle ssp. bestii Renauld & Bryhn, Bull. Acad. Int. Geog. Bot. 10: 7. 1901; Hygrohpnum bestii (Renauld &
Bryhn) Brotherus: H. molle var. bestii (Renauld & Bryhn) Habeeb; Hygrohypnella bestii (Renauld & Bryhn) Ignatov & Ignatova;
Limnobium bestii (Renauld &
Bryhn) Holzinger Plants
coarse and stiff, rarely soft, olive-green, often yellow or dull, yellowish green
with golden mottling, regularly silty. Stems
to 12 cm, often denuded from the base or bearing persistent, shredded leaf
bases, rarely foliose throughout; branching irregular; hyalodermis absent;
central stand weak or absent. Leaves
somewhat distant, weakly appressed-imbricate or erect when wet, variously
contorted when dry, ovate to broadly-ovate, (1--)1.5--2.5(--3) x 1--1.5(--2)
mm; apex obtuse, or somewhat acute; margins entire or uneven apically, rarely
denticulate, plane to broadly and shallowly concave, strongly decurrent or
scarcely so; leaf bases strongly adherent and persistent by the incrassate
basal cells and cortical stem cells; costa usually strong and double from a
massive base with one or both branches reaching mid-leaf or very strong and
single reaching beyond mid-leaf, often bearing 1--3 forks, yellow-green,
becoming brownish in age; basal cells usually strongly incrassate and
yellowish, turning yellow-brown in age, the pigmentation often creating a
radiating sunburst effect at and around the base of the costa; alar cells
undifferentiated, or forming an imprecisely defined group of quadrate,
short-rectangular or irregular cells; median leaf cells linear-flexuose to
broadly rhombic-flexuose, (40--)60--120(--170) \um, areolation homogeneous or
irregularly interspersed with very wide cells; apical cells usually rounded-quadrate to
rhombic; marginal cells from the proximal 1/3 to the distal 1/4 of the leaf
very long, 60--250 \um. Sexual
condition dioicous; inner perichaetial leaves linear-lanceolate, costa
absent, single to midleaf or short and double, multi-stratose through the
mid-line of the leaf, lamina 2-stratose. Seta
12--25 mm, red to dark, maroon-red. Peristome
endostome with 1--3 weakly appendiculate cilia. Irrigated, often silt covered rocks in montane streams; moderate
to high elevations, 1500--3000 m; Alta., B.C., N.B., N.S., Ont., Que.; Much confused in 4.
Hygrohypnum closteri ( Hypnum
closteri Plants
soft and spindly, dull, dirty green. Stems
to 15 cm, prostrate to somewhat ascending, frequently denuded at the
base, branching irregular; hyalodermis absent; central strand
well-developed. Leaves distant, uniformly straight, loosely patent when wet,
becoming somewhat erect spreading, markedly shrunken and twisted upon drying;
narrowly ovate, ovate-lanceolate to lanceolate, (0.3--)0.6--0.9(--1.75) X
(0.2--)0.3--0.4(--0.75) mm, plane or rarely weakly concave, margins entire,
apex acute; costa usually single reaching 1/2--1/3\x leaf length, much less
frequently short an double or single and forked; basal cells variable, little
changed from medial cells or shorter, longer and wider, alar cells usually
little different from adjacent basal cells or as a few gradually widened quadrate
or short-rectangular cells, medial cells fusiform or rhombic, straight or
flexuose, sometimes linear-flexuose, (23--)30--50(--63) X (4--)6--7(--13) \um,
marginal and apical cells shorter,. Sexual
condition autoicous, perigonia and perichaetia occurring individually or
in 1- or 2-sexual pairs; inner perichaetial leaves triangular-lanceolate,
erect, 1.5--2 mm, plane, not plicate, costa single, cells smooth. Seta 7--10 mm, yellowish or yellowish
red, Peristomial endostome with 1--3
cilia. Irrigated or submerged rocks in streams; Low to moderate
elevations, 20--1500; D.C., Hygrohypnum
closteri is an enigmatic little
plant that is so unlike the main body of Hygrohypnum
that it is surely ill-placed in the genus.
Indeed, the author and others have noted its Amblytegium-like appearance.
Perhaps molecular tools can resolve the issue. Sadly, its habitat
along the eastern seaboard of the flora region may be destroyed. 5.
Hygrohypnum cochlearifolium (Venturi in DeNotaris) Brotherus, Naturl. Pflanzenf. 1(3): 1039. 1909 Limnobium
cochlearifolium Venturi in De Notaris, Erbar.
Critt. Ital., ser 2, fasc. 10, n. 453. 1871; Hypnum goulardii Schimper; Calliergon
goulardii (Schimper) Kindberg; Hygrohypnum smithii
var. goulardii (Schimper) Wijk &
Margadant; Ochyraea cochlearifolia (Venturi
in DeNotaris) Ignatova & Ignatova Plants
very soft, forming loosely woven, easily fragmenting, often silt-clogged
patches or small, tightly woven patches, usually yellow to yellow-green with
conspicuous rusty mottling. Stems to 5 cm, usually shorter,
usually un-branched, or infrequently and irregularly so; hyalodermis absent;
central strand weak and poorly differentiated. Leaves crowded or very distant, when wet loosely imbricate or
spreading, upon drying either changing little or shrinking visibly, usually
ovate to very broadly ovate or ovate-elliptic, (0.5--)0.8--1.2(--1.5) x
(0.3--)0.6--1(--1.3) mm ; apex usually obtuse or rounded, rarely acute,
regularly cucullate; margins entire, recurved in small leaves, or mostly
plane in larger leaves; concavity conspicuous, very deep to cochleariform;
costa usually short and double with one arm reaching mid-leaf, sometimes
short and single to mid-leaf or absent; basal cells variable; alar cells
thin-walled, undifferentiated, or with a few quadrate, short-rectangular or
irregular cells, never forming a clearly, defined group; medial leaf cells
short fusiform, short linear-flexuose
or rhombic, 26--48(--55) x (4--)5--6(--8) \um; apical cells shorter to more
rhombic; marginal cells shorter. Sexual
condition poorly understood; perigonia not seen; perichaetia too few to
generalize. Seta 12--16 mm,
yellowish to reddish brown. Peristome
endostome with 2--3 cilia. Acidic rocks in irrigated streams or
on shaded, irrigated cliffs and boulders; moderate to very high elevations,1300--3700
m; Nunavut; Yukon; Alaska, Colo., Montana; Europe. Hygrohypnum
cochlearifolium is rare in the flora region and is
documented by eight examined specimens.
These specimens come from the far north or as disjunctions south along
the Rocky Mountains to 6.
Hygrohypnum duriusculum
(De Notaris) D. W. Jamieson, Taxon 29: 152. 1980 Limnobium
duriusculum De Notaris, Erb.
Crittog. Ital., 204. 1869; Calliergon
circulifolium (Müll. Hal. & Kindberg in Macoun) Kindberg; C. dilatatum (Wilson in Schimper) Kindberg;
C. pseudo-arcticum (Kindberg) Kindberg;
Hygrohypnella duriuscula (DeNotaris)
Ignatov & Ignatova; Hygrohypnum
dilatatum (Wilson) Loeske; H. eugyrium
var. dilatatum (Wilson in
Schimper) Grout; Hypnum circulifolium Müll.
Hal.. & Kindberg in Macoun; H.
dilatatum Plants
usually coarse and stiff, bright yellow-green, dull olive-green, dirty yellow
or yellow-brown, all with or without rusty mottling. Stems
to 7 cm, foliose throughout or commonly denuded from the base; branching irregular
and usually ascending; hyalodermis absent; central strand strong. Leaf
appearance varies within and between the wet and dry conditions, wet
leaves appressed-imbricate and sometimes secund or spreading and somewhat
contorted, upon drying all leaves exhibit varying degrees of shrinkage,
spreading or contortion, contortion may involve twisting to the left and
toward the stem or inrolling of the margins toward the costa with concomitant
twisting, very broadly-ovate, oval to orbicular, less often ovate, plane or
shallowly concave, (0.8--)1.1--1.7(--2.2) x (0.6--)0.8--1.3(--1.7) mm; apex
acute, obtuse or shortly apiculate; margins usually entire, rarely
denticulate, plane or narrowly recurved at the alar margin; leaf base often
narrowly decurrent and sometimes clasping the stem; costa short and double
with arms often reaching mid-leaf, sometimes single and forked reaching to
beyond mid-leaf; basal cells wider, longer, thicker-walled and often more
discolored than medial cells, alar cells in a well-defined group of quadrate,
short-rectangular or irregular, incrassate, usually discolored, plane or
often excavated cells; median leaf cells short to long-fusiform or
linear-flexuose, (26--)30--70(--90) x (3--)5--7(--9) \um.; apical and
marginal cells shorter. Sexual
condition autoicous, inner perichaetial leaves with apical, abaxial
laminal cells smooth. Seta 9--24
mm. yellowish red, red or maroon. Peristome endostome usually with 1--3
well-developed cilia. Irrigated, emergent acidic rocks in
montane streams; low to very high elevations, 200--3600 m; Hygrohypnum
duriusculum is at the center of a
much confused group of species.
Included are H. duriusculum, H.
molle, H. alpinum and H. bestii.
These species may be distinguished as follows: Hygrohypnum
duriusculum exhibits very broadly
ovate to oblong-elliptical, oval to orbicular leaves, alar cells forming a
well-defined broad group of quadrate, short-rectangular or irregular often
excavated cells with thickened, regularly discolored walls. Hygrohypnum
molle occurs only in western area
of the flora, leaves mostly ovate to broadly-ovate with an acute, but blunt
apex; alar cells essentially undifferentiated from surrounding cells;
moreover, leaves little changed from wet to dry condition and more or less
straight and loosely imbricate. Hygrohypnum alpinum is also a western species; leaves typically orbicular
with alar cells forming rectangular group of more or less rectangular or
irregular, enlarged, thin-walled cells.
Hygrohypnum bestii stands alone in having exceedingly
long marginal laminal cells, generally exceeding 60 \um. It should be noted that while H. duriusculum occurs across the
continent the plants from western 7.
Hygrohypnum eugyrium (Schimper) Loeske, Verh. Bot. Ver.
Brandenburg 46:198. 1905 Limnobium
eugyrium Schimper, Bryol. Eur. 6: 73, plate 579. 1855; Calliergon eugyrium (Schimper) Kindberg;
Hygrohypnum eugyrium var. mackayi (Schimper)
Brotherus; Pseudohygrohypnum eugyrium (Schimper)
Kanda Plants
yellow-green, pale green, bright green, often exhibiting
a golden-brown to deep metallic red mottling, most plants exhibiting a
striking satin-like lustre or sheen, infrequently becoming dark red, reddish brown
or brown in age. Stems to 6 cm, mostly
shorter, prostrate or ascending, branching irregular; hyalodermis poorly
developed as an epidermal layer with outer tangential wall slightly thinner
walled; central strand present. Leaves changing little from wet to
dry, variously loosely appressed or imbricate or loosely spreading, ovate,
oblong-lanceolate to lanceolate, rarely broadly-ovate or broadly
oblong-lanceolate, straight or falcate, generally quite concave, (0.9--)1.1--1.8(--2)
x (0.3--)0.5--0.8(--1.2) mm, leaf base clasping the stem, margins entire or
with a few small teeth in the apex, plane or folded along one side as a wing
or in-rolled from both margins in the distal half to become somewhat
tubulose, apex acute or gradually to abruptly long tapering, margins inrolled
just below the apex may give the appearance of an apiculus; costa mostly
short and double and slender, frequently with one or both arms reaching
mid-leaf, rarely single to mid-leaf or beyond; basal cells shorter or longer
and wider than medial cells, incrassate pitted and discolored, alar region of
6--12 enlarged or inflated, usually excavated quadrate to rectangular cells
in a clearly defined group, cell walls hyaline or dark red or reddish brown
in age, marginal alar cells always thin-walled while inner alar cells are
regularly incrassate and occasionally pitted, pigmentation occluding the
lumina in age, medial cells fusiform-flexuose or linear-flexuose, 45--75 x 4--5
\um,. Sexual condition autoicous; inner perichaetial leaves erect,
long, linear-lanceolate, tapering to an acute to acuminate apex, entire or
coarsely serrulate in the apex, costa variable, 2--4 plicae, cells smooth. Seta 13--16 mm, yellow-brown to red. Peristome endostome with 2--3 cilia. Irrigated acidic rocks in or along montane streams; low
to moderate elevations, 150--750 m; N.B., Nfld. and Labr. (Nfld.), N.S.,
Que.; Falcate leaved forms of Hygrohypnum eugyrium may
be confused with H. luridum and H. ochraceum. Hygrohypnum
eugyrium is set apart, most conspicuously, by quadrate to rectangular
alar cells conspicuously inflated and regularly excavated and in age becoming
a conspicuously red to reddish brown color, which often occludes cell
lumens. In addition, the hyalodermis
is much weaker and less conspicuous than that of H. ochraceum, and under a hand-lens or dissecting scope the
abaxial leaf surface exhibits a satin-like sheen. 8.
Hygrohypnum luridum (Hedwig) Hypnum
luridum Hedwig, Spec. Musc. Fond., 291. 1801; Calliergon pseudomontanum (Kindberg) Kindberg;
Hygrohypnum palustre (Hedwig) Loeske; H.
palustre var julaceum (Schleich. ex B.S.G.) Loeske; H. palustre var. subsphaericarpon (Schleicher ex Bridel)
Loeske; H. pseudomontanum (Kindberg in Macoun) Grout; Hypnum columbicopalustre Müll. Hal. & Kindberg in Macoun; H. palustre Plants
slender to robust, yellow-green to yellow-green with rusty mottling, less
often yellow-brown, bright-green, blackish green, regularly grading from one
color to another within the same plant. Stems
to 6 cm, mostly prostrate but ascending at the tip, usually foliose
throughout; branching irregular; hyalodermis absent; central strand
well-developed. Leaves variable, but changing little from wet to dry, lanceolate,
often oblong-lanceolate, ovate and occasionally broadly-ovate, (0.5--)1--1.5(--2.5)
x (0.25--)0.4--0.75(--1.1) mm, straight or falcate, rarely almost circinate,
mostly imbricate, often julaceous; apex acute or slightly short apiculate,
margins entire, regularly inrolled; costa single and short to percurrent or
short and double or absent, often all within the same plant; basal cells
wider and shorter than medial cells, medial cells short-rhombic to
linear-flexuose, (28--)30--55(--95) x (4--)5--7(--12) \um; alar area usually
present as a well-defined group of quadrate to short-rectangular or
irregularly shaped cells, thin and hyaline or incrassate and discolored
yellow-brown or reddish brown, plane or excavated and when excavated cells
may be inflated, marginal and apical cells shorter;. Sexual condition autoicous, inner perichaetial leaves lanceolate,
costa single, short and double or absent, cells smooth. Seta 8--24 mm, capsule exannulate. Peristome endostome with 1--3 poorly to well-developed cilia. Irrigated calcareous rocks, stones or wood or irrigated
with calcareous water in montane streams; moderate to very high elevations,
450--3200 m; Alta., B.C., Hygrohypnum
luridum is a highly variable species for which numerous
subspecific taxa have been recognized; there are, however, no reliable
distinguishing features among the supposed subspecific taxa. In 9.Hygrohypnum
molle (Hedwig) Loeske. Moosfl. Harz., 320. 1903 Hypnum
molle Hedwig. Spec. Musc. Frond., 73, plate 70, fig. 7--10. 1801; Calliergon molle (Hedwig) Kindberg; C.
submolle (Kindberg) Kindberg; Limnobium
submolle Kindberg; Ochyraea mollis (Hedwig)
Ignatov Plants
soft, yellowish green or olive-green. Stem
to 10 cm, procumbent, usually leafy throughout, branching irregular,
widely spaced, often attaining the length of the stem; hyalodermis absent;
central strand present. Leaves
closely to distantly spaced, loosely imbricate and straight, young branch
leaves slightly twisted at the apex when dry, otherwise leaves little
different wet or dry, broadly ovate, rarely ovate to almost orbicular,
(0.8--)1--1.75(--2) x (0.6--)0.75--1.2(--1.25) mm; apex tapering gradually to
an acute, but blunt tip; margins entire, undulating or finely denticulate in
the distal half, especially in the apex; concavity shallow to deep; costa
usually short and double, with slender arms, the longer reaching mid-leaf, or
just beyond; basal cells longer, shorter, and slightly more incrassate than
medial cells with few pits or none and discolored or not, alar cells undifferentiated or of a few
quadrate, short-rectangular or irregular cells, scarcely different from
surrounding cells; medial leaf cells rhomboid to linear-flexuose, (24--)32--52(--74)
x (3--)5--6(--8) \um; apical cells little different; marginal leaf cells 30--60
\um, rarely reaching 60 \um. Sexual
condition autoicous; inner perichaetial leaves with some apical cells
abaxially papillose by apically over-riding end walls. Seta
6--15 mm, orangish red, reddish brown to deep maroon. Peristome endostomial cilia
rudimentary or wanting. Irrigated or seepy acidic rocks in or along montane
streams; moderate to very high elevations, 650--3300 m; B.C.; Alaska, Calif.,
Hygrohypnum molle has been much
confused with H. duriusculum and H. bestii and less so with H. alpinum. The essential features of H. molle are the undifferentiated alar
cells of the broadly ovate, distinctly concave leaves, which taper to an
acute, but blunt, slightly denticulate apex.
In addition, the leaves are essentially straight and loosely imbricate,
little differing wet or dry.
Comparisons with H. alpinum, H.
duriusculum and H. alpinum can
be found in the discussion of H.
alpinum. 10.
Hygrohypnum montanum (Lindberg) Brotherus, Naturl. Pflanzenf.
1(3):1039. 1909 Amblystegium
montanum Lindberg, Musci Scand., 33. 1879; Calliergon montanum (Lindb.) Kindberg; Hygrohypnum eumontanum H.
A. Crum, Steere & L. E. Anderson; Limnobium montanum (Lindberg) Kindberg;
Ochyraea Plants
bright or dull-green, yellow or yellow-green, dark brown, in general only the
youngest parts are yellow to yellow-green. Stems to 2 cm, generally less, prostrate to slightly ascending at
the tips, branching irregular, hyalodermis absent, central strand absent. Leaves little different wet or dry,
variously straight or falcate and squarrose-canaliculate in the distal half,
upon drying shrinking laterally with a slight in-rolling of the margins with
a concomitant twisting in the leaf tip, usually ovate, sometimes
ovate-lanceolate, but may be broader or narrower, (0.3--)0.5--0.9(--1.1) x
(0.25--)0.3--0.5(--0.9) mm, broadly concave in the proximal half, apex acute
to somewhat acuminate, margins narrowly recurved in the proximal half, or
less often plane, coarsely to finely serrulate, most conspicuously in the distal
half or entire; costa slender, usually short and double; basal cells changing
little from medial cells or becoming wider, in either case becoming more
incrassate and irregularly pitted, alar cells undifferentiated or forming a
scarcely differentiated group of quadrate to short-rectangular or irregular,
incrassate, slightly pitted yellowish cells, medial cells short-fusiform to
long, linear-flexuose, (17--)25--50(--69) x (3--)4--5(--6) \um, cells toward
the apex little different, although a
few cells may be papillose by means of anteriorly over-riding end-walls. Sexual
condition autiocous; inner perichaetial leaves lanceolate with a long
tapering apex, costa variable, single and slender or broad and forking,
coarsely serrulate in the apex, cells smooth,. Seta 10--17 mm, yellowish red to red. Peristome endostome of 2--3 cilia. Irrigated, sand covered rocks in or beside montane
streams; moderate elevations, 500--700 m; N.B., N.S., Que.; Hygrohypnum
montanum is most easily recognized by a combination of individually variable
features; tiny leaves ovate to ovate lanceolate in shape, recurved proximal
leaf margin, serrulation of the distal leaf margins, and absence of a central
strand. Also useful, but difficult to
see are the few abaxial apical cells that are papillose by anteriorly
over-lapping end-walls. It is a puzzling little plant reminiscent of Campylium. Perhaps molecular work might
illuminate that point. 11.
Hygrohypnum norvegicum (Schimper) Amann, Fl. Mouss. Suisse
1:188. 1912 Limnobium
norvegicum Schimper, Bryol. Eur. 6:70. 576. 1853; Calliergon viridulum (Lindberg) Kindberg;
Limnobium viridulum (Lindberg) Kindberg;
Ochyraea norvegica (Schimp.) Ignatov
& Ignatova Plants
in small, soft, loosely to tightly woven patches, pale
yellow green, light brown with age. Stems to 3 cm, usually less than 1.5
cm, branching irregular; hyalodermis absent, central strand present. Leaves when wet, straight and loosely
imbricate to spreading, crisping upon drying to shrinking laterally and
concomitantly inrolling and twisting, usually ovate, less often broadly
ovate, plane to shallowly but clearly concave, (0.4--)0.5--0.8(--0.9) x (0.2--)0.4--0.5(--0.6)
mm; apex acute, occasionally obtuse, sometimes slightly squarrose, margins
entire, usually plane, or rarely narrowly recurved, mostly in the proximal 1/4
of the leaf, rarely reaching the shoulder before the apex; basal cells
variable; alar cells undifferentiated or forming a small, irregular group of
a few quadrate to short-rectangular cells; medial cells short-rhombic,
bacilliform, fusiform, to linear-flexuose, (16--)20--30(--48) x 5--6 \um;
apical and marginal cells shorter. Sexual condition autoicous, inner perichaetial leaves
lanceolate, acute or gradually tapering, costa slender, single or double to
midleaf, 2--4 plicae, cells smooth, margins entire or finely and irregularly
toothed. Seta 6--10 mm, yellow to reddish brown. Peristome
endostome with 2--3 well-developed cilia. Irrigated acidic rocks in montane streams; moderate to
high elevations, 650--1700 m; B.C.; Hygrohypnum
norvegicum remains a poorly
understood species. Eight North American
specimens are too few from which to develop a sound concept of its
distinctiveness and variability. The lone specimen from B.C. looks like a
very tiny H. molle. There are some
very small specimens of H.
cochlearifolium with which the B.C. specimen could be confused. In combination these characters serve to
distinguish H. norvegicum: tiny,
ovate leaves with acute apices, and loosely imbricate to spreading leaf
stance. 12.
Hygrohypnum ochraceum (Turner ex Hypnum
ochraceum Turner ex Wilson, Bryol. Brit., 400, plate 58. 1855; Calliergon ochraceum (Turner ex Plants
soft or coarse, bright shiny yellow-green, dull yellow-green, bright or dull
green, dull olivaceous green with or without rusty mottling, dirty brown,
rarely blackish or blackish green. Stems to 15 cm, prostrate and
creeping or ascending at the tip, tips straight or hooked, generally foliose
throughout or with shredded leaf-bases or denuded in the older extremities,
unbranched or irregularly branced, hyalodermis present as a single epidermal
layer of inflated, thin-walled, hyaline cells enclosing a cortex of 2--3 rows
of small, thick-walled yellow to reddish brown cells, central strand
well-developed. Leaves variable
among different plants or within individual stems or branches, crowded or
distant, loosely imbricate or spreading, straight or falcate;
ovate-lanceolate or lanceolate, infrequently ovate, rarely broadly-ovate,
(0.7--)1--1.8(--2.5) x (0.2--)0.5--0.8(--1.2) mm, apex acute to long, tapering acuminate,
obtuse or bluntish, margins entire except where minutely denticulate to
serrulate in the apex; costa variable, almost absent, short and double,
usually long and double with one or both arms reaching mid-leaf or beyond or
single to mid-leaf or beyond, or single to mid-leaf or beyond or single with
1--3 lateral forks; basal cells variable, usually wider but variously
shorter, longer or changing little from medial cells, becoming incrassate in
age; alar cells variable, quadrate, short-rectangular or sometimes linear,
thin-walled or slightly thickened, hyaline, almost never discolored, forming
an irregular group in 2--3 rows along the margin, the marginal row of which
forms a variable group of 3--4 or 5--7 cells that gradually transition from
quadrate or short-rectangular at the insertion to rectangular or linear
further up the margin, medial cells fusiform to linear, long-flexuose,
(30--)37--83(--120) x (4--)5--6(--8) \um, marginal cells shorter toward the
apex, but variable elsewhere. Sexual
condition dioicous, inner perichaetial leaves long-tapering lanceolate,
minutely serrulate at the apex, plicate, cells smooth, costa variable. Seta 16--31 mm, reddish brown. Peristome endostome with 1--3 cilia. Irrigated acidic rocks and wood in streams; low to very
high elevations, 200--3700 m; Greenland; Alta., B.C., Ont., N.B., Nfld.
(Nfld.), N.S. Que., Hygrohypnum
ochraceum is highly polymorphic. It
varies from compact specimens with falcate-secund leaves to those with long,
trailing stems with straight, widely spaced leaves. Unifying such plants is
their dioicous sexuality and a stem hyalodermis. With experience the need to cut stem
cross-sections can be circumvented by observing the marginal alar cells just above
the point of insertion. The most proximal cell is generally quadrate or very short-rectangular
while those above grade to longer rectangular to almost linear. Hygrohypnum
ochraceum has often been confused with H. luridum, which differs in being autoicous, a calcicole, lacks
a hyalodermis, and has a well-developed group of quadrate to
short-rectangular or irregular alar cells. 13.
Hygrohypnum polare (Lindberg) Loeske, Verh. Bot. Ver.
Brandenburg 46: 198. 1905 Hypnum
polare Lindberg, Oefv. K. Ak. Foerh. 23:540. 1867; Calliergon polare (Lindberg) Kindberg;
Hygrohypnella polaris (Lindberg)
Ignatov & Ignatova; Hygrohypnum
palustre var. ehlei (Arnell) Grout Plants
in appressed turfs or loose patches, golden-yellow, yellowish green, rarely
bright green. Stems to 13 cm, prostrate, ascending or erect, branching absent
or irregular from the base, mostly fastigiate; hyalodermis incomplete, an
outer row of thin-walled cortical cells, evident in older stems only as the
thickened inner concave walls, central strand well-developed, discolored in
age. Leaves appressed-imbricate to loosely spreading, differing wet or
dry, ovate-lanceolate, oblong-lanceolate, elliptic or broadly so, straight or
falcate, shallowly to deeply concave, rarely almost plane, (0.9--)1.1--1.6(--2.1)
x (0.6--)0.75--1(--1.1) mm; apex
tapered to an acute or apiculate point, or deeply concave-cucullate with an
often recurved apiculus; margins entire and plane, sometimes slightly
inrolled near the apex, margins in falcate leaves inrolled rendering the leaf
tubulose in the distal half; costa very stout, single, ending shortly below
the apex, or percurrent in the apiculus,
rarely forked, never short and double; basal cells shorter and wider
than medial cells, incrassate and yellowing in age, alar cells numerous, in a
well-defined group of quadrate or short-rectangular, usually thin-walled,
hyaline cells, becoming brown in age; median leaf cells fusiform to long,
linear-flexuose, (33--)40--50(--65) x 5--6(--8) \um; apical cells shorter,
usually rhomboid. Sexual condition dioicous; inner perichaetial leaves long-lanceolate,
plicate, costa single and strong, cells smooth, apex gradually tapering,
becoming frayed in age. Seta 10--12
mm. Peristome unknown. Acidic rocks in montane or high latitude streams; moderate
elevations, 900--1400 m; Greenland; B.C., Nfld. (Nfld.), Hygrohypnum
polare is easily recognized by the strong, single costa and the
outer layer of thin-walled cortical cells in the stem. The group of quadrate
alar cells and the usual leaf concavity provide confirmation. 14.
Hygrohypnum smithii (Swartz in Liljeblad) Brotherus.
Natürl.. Pflanzenfam. 1(3):1039. 1909 Leskea
smithii Swartz in Liljeblad. Svensk. Fl., ed. 3, 549. 1816; Calliergon arcticum (Sommerfelt) Kindberg;
Hypnum torrentis Müll. Hal. & Kindberg in Macoun; Ochyraea smithii (Swartz in Liljeblad)
Ignatov & Ignatova Plants
very coarse and stiff. dull, dark green, olivaceous green, or black, all with
or without golden-green or golden-brown mottling. Stems to 8 cm, branching absent or irregular, proximal stems and
branches denuded or with persistent, shredded leaf bases, hyalodermis absent,
central strand well developed. Leaves stiffly and loosely imbricate to
erect-spreading, shrinking and twisting upon drying, usually broadly ovate,
elliptical or orbicular, sometimes ovate, transverse or triangular, plane or
shallowly concave, (0.6--)0.8--1.2(--1.5) x (0.4--)0.6--1.2(--1.4) mm; apex
usually obtuse or rounded; margins entire or weakly denticulate; costa stout,
single to 3/4\x leaf length, often forked, occasionally short and double; basal
cells generally wider, longer, and more incrassate than medial cells, also
yellowing; alar cells quadrate to rectangular, incrassate and yellowing, not
forming a clearly recognizable or differentiated group; medial cells
rhomboid, fusiform to short, linear-flexuose, 22--48(--64) x (4--)5--7(--10) \um;
apical cells rhombic or rounded; margins often bordered by an ill-defined row
of short cells. Sexual condition autiocous,
inner perichaetial leaves lanceolate, costa strong and single, margins
entire, cells smooth, apex acute or obtuse, with or without a few teeth. Seta 8--17 mm, red or brown. Peristome endostome with 1--3 poorly
to well developed cilia. Irrigated to emergent acidic rocks in montane streams,
occasionally on rocks or wood in slow moving water or ponds; moderate to very
high elevations, 550--3100 m; Alta., B.C., Nfld. (Nfld.), N.S., Que.; Alaska,
California, Colo., Mont., Wash.; Greenland; Atlantic Islands (Iceland),
Europe. Hygrohypnum
smithii is a well-defined species, easily recognizable by its
coarse, rigid habit, usually broadly-ovate to orbicular leaves, and stout,
usually single costa. 15.
Hygrohypnum styriacum (Limpricht) Brotherus, Natürl. Pflanzenfam.
1(3):1039. 1909 Hypnum
styriacum Limpricht,
Flora ( Plants
soft to slightly rigid, usually dull yellow-green with rusty mottling, less
often dirty, brownish yellow or uniformly dull green. Stems
to 6 cm, foliose throughout or denuded in older extremities, branching
irregular, hyalodermis absent, central strand strong. Leaves slightly crowded to clearly distant, spreading when wet,
or slightly falcate, upon drying shrinking laterally and twisting apically or
spreading, weakly imbricate or falcate, ovate, straight or falcate, broadly
concave when wet, (0.7--)1--1.75(--2) X (0.3--)0.5--1(--1.1) mm, apex
abruptly acuminate, less often gradually so, sometimes sharply reflexed, apex
and margin entire; costa strong and thick, short and double, single or
forked, or infrequently single beyond mid-leaf; basal cells slightly wider
than medial cells; alar cells undifferentiated or recognizable as a few
quadrate or short-rectangular cells grading imperceptibly into other basal or
proximal medial cells; medial cells generally short, variously rhombic,
short-fusiform or bacilliform, thick-walled, (18--)28--40(--50) x (4--)5--7(--9)
\um; cells toward the margins or apex little changed or shorter. Sexual condition autoicous, a single
perigonium situated immediately beside a single perichaetium or between 2--4
perichaetia, in all cases the perigonial-perichaetial complex is enclosed
within 2--3 small bracts, this complex borne in the axil of a vegetative
leaf. Seta 9--21 mm, reddish yellow
to red. Peristome endostome of 2--3
sometimes poorly developed cilia. Irrigated, emergent acidic rocks in montane streams; high
to very high elevations, 2000--3700 m; Alta., B.C.; Hygrohypnum
styriacum is a distinctive species, but one sometimes mistaken for
small, falcate-leaved forms of H.
luridum. At present this is only a problem in western The perichaetia and perigonia are typically remote from
each other in autoicous species of the genus.
Hygrohypnum styriacum is
also autoicous, but in H. styriacum
a single, normal perigonium is found beside a single, typically formed
perichetium or between 2--4 perichaetia. In all cases the complex is
subtended or enclosed by 2--3 small bracts, and the whole is borne in the
axil of a single vegetative leaf. 16.
Hygrohypnum subeugyrium (Renauld & Cardot) Brotherus,
Natürl. Pflanzenfam. 1(3): 1039. 1909 Hypnum
subeugyrium Renauld & Cardot, Bot. Gaz. 22: 52, plate 4. 1896; Calliergon subeugyrium (Renauld &
Cardot) Kindberg; H. eugyrium var. subeugyrium (Renauld & Cardot) Grout; H. eugyrium var. miquelonense (Renauld & Cardot)
Grout; Pseudohygrohypnum subeugyrium (Renauld
& Cardot) Ignatov & Ignatova Plants
at stem and branch tips yellow-green, bright green or
dark, metallic-red, becoming reddish brown, maroon-red, reddish black or
brownish black in older extremities. Stems
to 6 cm, extremities mostly denuded, branching irregular, hyalodermis
absent, central strand poorly developed or absent. Leaves
little different wet or dry, straight, loosely imbricate or
falcate-imbricate, sometimes slightly complanate, narrowly ovate to ovate or
oblong to oblong-lanceolate, falcate-secund or straight, symmetrical or
sometimes asymmetrical, (0.9--)1--1.5(--2) x (0.3--)0.5--0.7(--0.8) mm,
shallowly concave in broad leaves to deeply so in narrower leaves, margins
entire and plane, apex gradually to abruptly acute to slightly acuminate tip,
apical margins are usually entire, but most stems and branches will exhibit a
few leaves that have abruptly acute apices that are slightly denticulate or
serrulate; costa slender, short and double, or absent, rarely single and
slender; basal cells shorter and wider that medial cells, alar cells
variable, nearly undifferentiated or forming an irregular group of quadrate,
short-rectangular or irregular, strongly incrassate, yellowish or reddish brown
cells, or exhibiting a basal row of enlarged incrassate cells surrounded by a
few quadrate or irregular cells, medial cells long, linear-flexuose, (40--)45--80(--114)
x (4--)5--6(--7) \um, becoming shorter toward the apex. Sexual condition autoicous, inner perichaetial leaves
ovate-lanceolate to long, triangular-lanceolate, to 5 mm, erect, costa
absent, short and double or single to mid-leaf, margins entire save a few
fine apical teeth, cells smooth. Seta 13--22
mm, annulus present. Peristome
exostome with 1--3 well-developed cilia. Acidic rocks in streams; low to moderate elevations, 0--1500
m; St Pierre and Miquelon; Nfld. (Nfld.), N.B., N.S., Ont., Que.; N.H., N.Y.,
Hygrohypnum
subeugyrium is an enigmatic species
I am not at all convinced truly belongs in the genus. In any event, H. subeugyrium can be identified by
the combination of dark pigmentation, alar differentiation, and leaf tip
morphology. Save for stem and branch tips, the older extremities of this
species are darkly pigmented reddish brown, reddish black or brownish black.
The transition from the yellow-green stem and branch tips to the darker,
older extremities can be quite abrupt.
Alar differentiation is clear, but variable even among leaves on the
same axis. They may form an irregular group of quadrate or short-rectangular
shaped, strongly incrassate, yellowish or reddish brown cells or, as a basal
row of enlarged, incrassate cells surrounded by a few that are quadrate or
short-rectangular, both alar expressions may be excavated. Such alar cells
are clearly different from the regularly inflated alar cells of H. eugyrium. The most important identifying
feature is the leaf apex, but 10 to 20 leaves from 1 or 2 stems must be
examined as a unit. Here, H.
subeugyrium is most easily recognized by the regular occurrence of a few
leaves with an abruptly acute leaf apex that are minutely denticulate to finely
serrulate among other leaves with entire apical margins. |
