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BFNA Title: Ephemeraceae |
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Level R Brum+ EPHEMERACEAE Schimper Virginia S. Bryan Plants leafy ephemerals, less than 3 mm,
solitary, scattered, or gregarious on sparse or abundant protonemata with
upright, aerial, determinate branches, green, pale-yellow, or brown. Stem virtually lacking or to 1 mm (to
3.7 mm in Micromitrium synoicum),
rhizoids absent or few. Leaves rarely
more than 12, the proximal small, broadly triangular to ovate, ecostate, apex
acuminate, the distal becoming larger, linear, lanceolate, or ligulate, with
or without shoulders, margins distal to the middle entire, serrulate,
serrate, or spinose, apex acuminate; costate or ecostate; laminal cells lax
and transparent, long-rhomboidal to rectangular, in some species becoming
denser distally, smooth, papillose by projecting distal ends, or spinose. Specialized asexual reproduction by
fragments and rarely by thick-walled elongate, swollen protonematal segments,
commonly brown, and persisting on or in the soil. Sexual condition autoicous, dioicous, or synoicous. Perigonia arising from the
protonemata, from rhizoids, or just proximal to the perichaetium; small,
bud-like with ecostate leaves of lax areolation, broadly triangular to
broadly ovate. Perichaetium
consisting of the 1--3 most distal leaves, typically the largest and best
developed. Vaginula conspicuous. Sporophytes 1--3 per perichaetium
with immersed to emerging capsules. Seta
virtually lacking or very short. Capsule
globose or ovoid, without or with an apiculus, cleistocarpous or opening
along an indistinct or distinct ring of cells near the equator; exothecium of
1--2 layers of lax and thin-walled cells; stomates lacking or superficial
with two guard cells. Calyptra
persistent, mitrate, and minute, or fugacious, mitrate or cucullate, and
irregularly lobed or torn at the base, covering up to 2/3 of the capsule. Spores appearing reniform, globose,
or variously angled, 20--120 µm, ranging from barely papillose to coarsely
warty, the elaboration often correlating with degree of maturity, usually
bearing small remnants of a hyaline membrane, orange, red, brown, or black. Genera 2,
species ca. 35 (2 genera, 8 species, 2 varieties in the flora): temperate and
tropical regions, nearly worldwide. The
Ephemeraceae are usually found in sunny or partly shaded areas, on moist or drying
disturbed soil where there is little competition from more persistent mosses
and larger plants. They are visible for the most part as patches of greenish,
alga-like protonemata with minute leafy plants and are best seen in the field
when the protonemal mass is most abundant and green, with leafy plants that
are green and approaching maturity. The
distinguishing characters of the leaves are derived from the largest, usually
the most distal, leaves. The middle and proximal leaves vary in shape, marginal
cells, and costal development. For example, the distal leaves bear the
well-developed costa, but the proximal leaves are usually ecostate, and the
middle leaves vary from ecostate to weakly or markedly costate. In the
nominally ecostate species the proximal and middle leaves are ecostate, but
the largest leaves, while in a strict sense ecostate, may have in the costal
position thicker walled cells or a few undifferentiated cells in a double
layer. As seen in cross-section, the double-layered cells are not organized
as a costa and do not differ from other laminal cells, except that they may
have very slightly thicker walls. In surface view the double layer is barely
distinguishable. SELECTED
REFERENCE Bryan, V. S. and L. E. Anderson. 1957. The Ephemeraceae in North
America. Bryologist 60: 67--102. 1. Calyptra minute, tightly adherent at
or near the apex of the capsule, persistent; capsule cleistocarpous or with a
ring of differentiated cells at or just distal to the equator, ± globose,
lacking a well-developed, multicellular apiculus; costa commonly lacking, but
occasionally suggested by a few median cells with thick walls or in a short
and indistinct double layer distal to the leaf middle; laminal cells lax,
hyaline, smooth . . . . 1. Micromitrium p. xxx 1. Calyptra
covering most of the distal half of the capsule, fugacious; capsule
cleistocarpous, ovoid, and distinctly apiculate; costa well-developed, except
mostly lacking in Ephemerum serratum;
laminal cells of the leaves lax in the proximal half and in the distal half
firmer, smaller, and usually papillose . . . . 2. Ephemerum p. xxx 1.
MICROMITRIUM Austin, Musci Appalach. 45. 1870 • Latin
micro, small, and mitra, headband, in reference to the
small calyptra Nanomitrium Lindberg, Not. Sällsk. Fauna Fl. Fenn.
Förh. 13: 408. 1874 Stems lacking or less than 1 mm, but up to 3.7 mm in M. synoicum. Leaves usually somewhat shriveled or contorted when dry; costa
commonly none, but occasionally suggested by a few median cells with thick
walls or by a short and indistinct double layer beyond the middle; laminal
cells lax, hyaline, non-papillose. Sexual
condition synoicous or dioicous. Capsule
cleistocarpous or dehiscing along a ring of differentiated cells at or distal
to the equator, globose or subglobose, without a multicellular apiculus, less
than 0.4 mm from base to apex; exothecium of 1--2 cell layers; columella
lacking in maturing capsules. Calyptra
persistent, minute, scarcely more than the remnants of the archegonial venter
and neck, tightly adherent at or near the capsule apex, less than 0.16 mm. Species ca. 9
(4 in the flora): temperate and tropical regions nearly worldwide. Micromitrium differs from Ephemerum in having a persistent, minute calyptra, consisting of
merely the archegonial neck and distal portion of the venter, a capsule that
is globose and regularly dehiscent in most species, and also in having
usually ecostate leaves with leaf cells that are large, hyaline, and
non-papillose. Except for M.
megalosporum and M. wrightii, Micromitrium also differs in having an
operculum (though rudimentary), no spore sac, and no stomates. Micromitrium megalosporum and M.
wrightii resemble Ephemerum in
having a usually cleistocarpous capsule, an exothecium of two layers, and stomates.
Cytological characters confirm the distinctness of the two genera. At the
time of meiosis Micromitrium
capsules are remarkably smaller than mature capsules, while capsules of Ephemerum, at the time of meiosis, are
approaching their mature size. A difference in size is also seen in the spore
mother cells undergoing meiosis: in the species of Micromitrium that have been studied cytologically, M. tenerum
(as Nanomitrium austinii) and M. megalosporum (as N. megalosporum),
the spore mother cells are very small and include 10, 11, or 22 chromosomes,
in comparison with the large spore mother cells of Ephemerum with 27 chromosomes (V. S. Bryan 1957). In the latter,
meiotic chromosome configurations occupy only a small volume of the large
spore mother cells. SELECTED
REFERENCES Bryan, V. S. 1957. Cytotaxonomic studies in the Ephemeraceae and
Funariaceae. Bryologist 60: 103--126. Crosby, M. R. 1968. Micromitrium Aust., an earlier name
for Nanomitrium Lindb. Bryologist
71: 114--117. 1.
Capsules dehiscent by a ring of differentiated cells at or distal to the
equator; exothecial cells in 1 layer; stomata lacking; spores 28--45 ´ 20--37
µm. 2.
Stems 0.2--3.7 mm, usually 0.7--2.2 mm; leaves erect, lanceolate, margins
usually ± incurved distal to the middle; entire
or nearly so . . . 1. Micromitrium
synoicum 2.
Stems usually lacking, but sometimes up to 1 mm; proximal leaves spreading,
distal erect, lanceolate to ligulate, margins plane, usually serrulate distal
by protruding cell apices, or almost entire . . . . 2. Micromitrium tenerum 1.
Capsules cleistocarpous or rarely dehiscent by a ring of differentiated cells
distal to the equator; exothecial cells in 2 layers, stomata present; spores
50--84 ´ 37--67 µm. 3.
Distal leaves broadly ovate-lanceolate and somewhat clasping at base, less
than 0.43 mm wide; stomates in distal half of capsule . . . 3. Micromitrium megalosporum 3.
Distal leaves linear-lanceolate, rarely with toothed shoulders, less than 0.26
mm wide; stomates in proximal half of capsule. . . 4. Micromitrium wrightii 1. Micromitrium synoicum (James) Austin
in Sullivant, Icon. musc. Suppl. 22. 1874 Ephemerum
synoicum James, Trans.
Amer. Philos. Soc. N.S. 9: 106. 1865; Nanomitrium
synoicum (James) Lindberg Plants scattered or gregarious in persistent,
but not usually abundant protonemata, pale green. Stems (0.2--)0.7(--3.7) mm. Leaves
erect, lanceolate, often with a broad base, narrowly acuminate,
(0.85--)1.8(--2) ´ 0.27(--0.4) mm, margins usually ± incurved beyond the middle, entire or nearly so. Sexual condition synoicous. Capsule dehiscing by a ring of
differentiated cells at or distal to the equator, red-brown or red-black,
globose or slightly flattened, slightly apiculate; exothecial cells in 1
layer, stomates none. Spores fewer
than 100; various shapes, proximal face only rarely concave, (30--)37(--40) ´
(23--)30(--33) µm, dark red or dark brown. Capsules
mature summer--winter. Drying or dried ponds, edges of lakes or streams, bare
soil in open forests; 10--500 m; Fla., Ga., Iowa, Ky., La., Mo., N.J., N.Y.,
N.C., Ohio, Oreg., Pa.; Asia (Japan). Calyptras in M. synoicum often are acentric, and as
many as three capsules may mature within one perichaetium. Mature plants may
persist with the capsule or capsules surrounded by only the bases of the
leaves, the distal portions apparently eroded away. 2. Micromitrium tenerum (Bruch &
Schimper) Crosby, Bryologist 71: 116. 1968 Phascum
tenerum Bruch &
Schimper, Laubm. Eur. Monogr. Phascum 2. 1835; Micromitrium austinii Sullivant; Nanomitrium austinii (Sullivant) Lindberg; Nanomitrium austinii var.
floridanum Grout Plants scattered or gregarious in sparse
remnants of protonemata, pale to bright green. Stems usually lacking, but rarely to 1 mm. Leaves spreading proximally, distally erect and lanceolate to
ovate, obovate or ligulate, broadly to slenderly acuminate, less than 2.4 ´ 0.5 mm,
margins plane, entire proximally, distally entire to serrulate. Sexual condition synoicous or
dioicous. Capsule dehiscing by a
somewhat indistinct ring of cells distal to the equator, orange-brown to
black, ± globose with a barely discernable
apiculus or with a dome-shaped apical cell; exothecial cells in 1 layer,
stomates none. Spores about 100,
reniform to globose, with or without a concave proximal face, 27--45 ´ 20--37
µm, orange-brown to brown or black. Capsules
mature summer--spring. Bare soil in old fields, drying ponds, moist or swampy
woods, banks of streams; 5--1000 m; B.C., N.S., Que.; Conn., Fla., Ga., Ill.,
Iowa, Ky., La., Maine, Md., Mich., Miss., N.J., N.Y., N.C., Ohio, Pa., S.C.,
Tenn., Va., W.Va.; West Indies (Puerto Rico, Virgin Islands); Central America
(Panama); South America (Brazil); Europe; Asia (China, Japan, Korea, Tibet);
Africa (Zimbabwe); Pacific Islands (New Zealand). Many specimens
include plants with leaves in which two or three cells in a double layer can
be found in a median position, just distal to the middle of the leaf. The
walls are not differentiated in any way and their presence does not suggest
even a meager costa. As in M. synoicum
and M. megalosporum, mature
capsules of M. tenerum may persist
after the leaves have eroded away. Micromitrium
synoicum and M. tenerum are
remarkably similar, but are distinguished by stem length and leaf size and
shape. Micromitrium tenerum is
stemless or has very short stems, and M.
synoicum has distinct stems. The somewhat longer leaves of M. tenerum have plane margins that may
be almost entire, but are usually serrulate distally, while the leaves of M. synoicum are commonly incurved
distal to the middle with almost invariably entire margins. 3. Micromitrium megalosporum Austin,
Musci Appalach. 47, p. 11. 1870 Ephemerum
megalosporum (Austin)
E. S. Salmon, J. Linn. Soc., Bot. 34: 166. 1899; Nanomitrium megalosporum (Austin) E. Britton Plants scattered or gregarious in usually
sparse protonemata, yellow-green to orange-brown. Stems less than 0.2 mm. Leaves
erect or spreading, broadly ovate-lanceolate and somewhat clasping at
base, acuminate, (0.5--)1.0(--1.1) ´ (0.14--)0.4(--0.43) mm, margins
usually + incurved beyond the middle, entire proximally and distally
entire to serrulate. Sexual condition
synoicous. Capsule cleistocarpous
or rarely dehiscing by a ring of differentiated cells distal to the equator,
orange-brown, globose or slightly flattened, rarely broadly ovoid, with a
short, broad apiculus; exothecial cells in 2 layers, stomates confined to
distal half, sometimes lacking. Spores
fewer than 100, various shapes, proximal face only rarely concave,
(55--)65(--83) ´ (37--)43(--67) µm, orange-brown. Capsules
mature summer--winter, with some capsules persisting through spring with
leaves intact or eroded. In sun or partial shade, unfertilized bare soil,
sparsely vegetated turf; 5--700 m; Ark., Conn., Fla., Ga., La., Maine, Md.,
Mich., Miss., Mo., N.J., N.C., Pa., Wis.; W. Indies (Cuba); Asia (Japan);
Africa (Cameroon). In immature
plants of M. megalosporum the
capsules may be almost completely obscured by the clasping proximal halves of
the leaves. Mature specimens can often be detected by a distinctive
orange-brown coloration of the capsules, spores, and sometimes of the leaves.
The plants frequently persist with intact or dehisced capsules among remnants
of leaves, and the dehisced capsules often appear as open cups of
orange-brown spores, not obscured by leaves. Chromosome studies have been
carried out on only two taxa of Micromitrium
(as Nanomitrium): M. tenerum n = 10, 11 (as N. austinii) and M. megalosporum (n = 22). On the basis of this polyploid
series and on other characteristics as well, the latter was transferred back
to Micromitrium from Ephemerum, species of which have a
chromosome number of n = 27 (V. S. Bryan 1957). 4. Micromitrium wrightii (J. K. A.
Müller) Crosby, Bryologist 71: 116. 1968 Ephemerum
wrightii J. K. A.
Müller, Linnaea 43: 351. 1882; Nanomitrium
wrightii (J. K. A. Müller) V. S. Bryan & L. E. Anderson Plants scattered in abundant protonemata,
green. Stems virtually lacking. Leaves erect, linear-lanceolate,
rarely with narrow, toothed shoulders, gradually and slenderly acuminate,
(1--)1.3(--2.0) ´ (0.15--)0.2(--0.26) mm, margins plane,
entire or with short single or double teeth distally. Sexual condition synoicous or dioicous. Capsule cleistocarpous or rarely dehiscing by a ring of
differentiated cells distal to the equator, yellow- to orange-brown, globose
or slightly flattened, slightly apiculate; exothecial cells in 2 layers,
stomates numerous and confined to proximal half. Spores fewer than 100, various shapes, proximal face not concave,
(50--)67(--84) ´ (40--)56(--66) µm, red-brown or dark
brown. Capsules
mature year around. Soil in shaded ravines, drying mud, clay in dry sloughs;
5--100 m; known from 5 or fewer localities: La., Tex.; West Indies (Cuba). Although the
leaves of M. wrightii are most
accurately described as ecostate, the largest leaves may have suggestions of
a costa. Some have merely thick-walled cells in the median part of the leaf,
and others may have + 3 median, undifferentiated cells in a double
layer. OTHER
REFERENCES Bryan, V. S. 1957. Cytotaxonomic studies in the Ephemeraceae and
Funariaceae. Bryologist 60: 103--126 2. EPHEMERUM
Hampe, Flora 20: 285. 1837, name conserved • Greek
ephemeros, of short duration Stems lacking. Leaves
scarcely contorted when dry; costa well-developed, except generally lacking
or weak in E. serratum; laminal
cells lax in the proximal half of the leaf, in the distal half firmer,
smaller, and usually papillose. Sexual
condition dioicous or autoicous, commonly rhizautoicous. Capsule cleistocarpous, ovoid and
distinctly apiculate, more than 0.5 mm from base to apex; exothecium of 2
cell layers; columella present in maturing capsules of E. cohaerens, but in
other species visible only as pigmented areas at base and tip of the spore
sac. Calyptra fugacious,
cucullate, sometimes lobed or torn at the base, covering the distal 2/3 of
the capsule, mostly more than 0.2 mm. Species ca. 28
(4 in the flora): temperate and tropical regions nearly worldwide. All Ephemerum taxa in the flora have the
same chromosome number, n = 27. Mixed colonies are common, although
hybrid forms are not evident. To a large extent, the species occupy similar
ranges. 1.
Leaves ecostate or in the distal two-thirds very weakly costate . . . 1. Ephemerum serratum 1.
Leaves distinctly costate, at least distal to the middle. 2.
Distal laminal cells spinulose or spinose. . . 4. Ephemerum spinulosum 2.
Distal laminal cells smooth or papillose. 3.
Distal laminal cells smooth, in ±
diagonal rows. . . 2. Ephemerum
cohaerens 3.
Distal laminal cells papillose in ±
vertical rows. . . 3. Ephemerum
crassinervium 1. Ephemerum serratum (Hedwig) Hampe, Flora
20: 285. 1837 Phascum
serratum Hedwig, Sp.
Musc. Frond. 23. 1801; Ephemerum
serratum var. minutissimum
(Lindberg) Grout Plants less than 2.0 mm, gregarious in
persistent matted protonemata. Leaves
linear-lanceolate to ovate-lanceolate, sometimes narrowed from distinct
shoulders, (1--)1.3(--2.4) ´ (0.17--)0.2(--0.3) mm; margins usually
coarsely and irregularly serrate distal to the proximal third, often with
spines, but varying to scarcely serrate; apex tapering gradually to a sharply
pointed acumen, lacking papillae; costa usually lacking, but sometimes
suggested by a few thick-walled cells or an obscure double layer of
undifferentiated cells, smooth; areolation lax proximally and somewhat firm
distal to; median laminal cells in vertical rows, smooth; distal laminal
cells smooth. Capsule with
columella resorbed before meiosis; stomates only at the base. Spores spherical or reniform,
(55--)70(--106) ´ (27--)53(--75) µm. Capsules
mature year around, mostly in autumn. Basic habitats more often than other
species of the family, meadows, pastures, drying and dried soil; 5--1150 m;
N.B., N.S., N.W.T., Ont., Que., Sask.; Ala., Calif., Conn., Fla., Ind., Ky.,
La., Maine, Md., Mass., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Oreg., Pa.,
S.C., Tenn., Tex., Va., W.Va., Wis.; South America (Brazil); Europe
(Sardinia); Asia (China); Africa (South Africa); Pacific Islands (New
Zealand). The serrations
of the leaf margins vary markedly, from barely serrate to long spinose. In
general, plants of E. serratum from eastern North America
tend to be more strongly serrate than plants from California and Oregon,
although barely serrate plants from the east have been seen as well as
distinctly serrate plants from the west. Mature capsules frequently persist
with only the remnants of leaves remaining, the distal portions of the leaves
apparently eroded away. Rarely, thick-walled, elongate, brown structures
occur on the protonemata and they may serve as diaspores. 2. Ephemerum cohaerens (Hedwig) Hampe,
Flora 20: 285. 1837 Phascum
cohaerens Hedwig, Sp.
Musc. Frond. 25. 1801; Ephemerum
cohaerens var. flotowianum
(Funck) Hampe Plants less than 2.5 mm, gregarious in thin,
usually persistent protonemata. Leaves
broadly lanceolate to oblong-lanceolate, sometimes amplectant, usually
abruptly narrowed from distinct, asymmetric shoulders, (1--)1.5(--2.2) ´
(0.17--)0.3(--0.5) mm; margins serrate, commonly spinose at the shoulders,
with one shoulder more deeply incised and less regularly spinose or dentate
than the other; apex subulate, sharply pointed, and sometimes recurved; costa
occasionally lacking at the base, strong distally, percurrent, excurrent, or
ending near the apex, toothed abaxially; areolation lax in proximal third, more
compact distally; median laminal cells usually in diagonal rows upward from
costa to margin, smooth; distal laminal cells smooth. Capsule with columella occasionally persisting to maturity;
stomates scattered throughout. Spores
spherical or reniform, (47--) 70 (--95) ´ (40--) 60 (--62) µm. Capsules
mature year around. Moist or drying disturbed soil, occasionally in bogs;
5--500 m; N.S., Ont., Que.; Ala., Ark., Conn., Del., Fla., Ga., Ill., Iowa,
Kan., Ky., La., Md., Mich., Minn., Mo., Nebr., N.H., N.Y., N.C., Ohio, Okla.,
Pa., Tenn., Tex., Va., W.Va.; Europe; Asia (China, Japan). The laminal
cells at mid-leaf are arranged typically, but not invariably, in diagonal
rows from the margin near the shoulders proximally toward the costa.
Occasionally, one finds plants with the typical leaf shape, but in which the
laminal cells run almost parallel to the costa. 3. Ephemerum crassinervium (Schwägrichen)
Hampe, Flora 20: 285. 1837 Phascum
crassinervium
Schwägrichen, Species Musc. Frond. Suppl. 1(1): 4. 2. 1811 Plants less than 2.5 mm, scattered in sparse
protonemata. Leaves lanceolate,
broadly linear or ligulate, acuminate, sometimes narrowed distally from
shoulders, 0.8--2.5 ´ 0.15--0.4 mm; margins serrulate or
serrate, with teeth sometimes recurved up to 45°; apex
acuminate and papillose; costa at the base thin or not always apparent,
stronger distally, often filling the acumen, percurrent or excurrent,
papillose; areolation firm proximally and distally compact to dense; median
laminal cells in + vertical rows, smooth or slightly papillose; distal
laminal cells papillose. Capsule
with columella resorbed before meiosis; stomates in proximal half or
scattered throughout. Spores
various, 43 ´ 35 to 120 ´ 80 µm Varieties 2 (2
in the flora): North America, Europe. 1. Distal
leaves lanceolate to broadly linear and acuminate, with compact to rather
dense areolation in the distal two-thirds . . . 3a. Ephemerum crassinervium var. crassinervium 1. Distal leaves
broadly lanceolate to oblong-lanceolate or ligulate and subulate, often
narrowed from a slight to prominent shoulder, densely papillose in the distal
half . . . 3b. Ephemerum crassinervium
var. texanum 3a. Ephemerum crassinervium (Schwägrichen)
Hampe var. crassinervium Phascum
crassinervium
Schwägrichen, Sp. Musc. Frond. Suppl. 1(1): 4. Plate 2. 1811; Ephemerum crassinervium var. papillosum (Austin) Renauld &
Cardot Plants less than 2.5 mm. Leaves broadly linear to lanceolate, (0.8--)1.4(--2.5) ´
(0.15--)0.2(--0.4) mm; margins serrulate to strongly serrate distal to the
proximal third; apex slenderly acuminate, papillose; costa not always
apparent at the base, often filling the acumen, percurrent; areolation
compact distally; median laminal cells smooth or slightly papillose; distal
laminal cells somewhat papillose. Capsule
with very few stomates, mostly near the base. Spores spherical or reniform, (43--)75(--107) ´
(35--)50(--75) µm, orange-brown. Capsules
mature year around. Moist or drying disturbed soil; 7--1000 m; Ont., Que.,
Sask.; Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Kan., Ky., La., Md.,
Mich., Minn., Miss., Mo., Neb., N.H., N.J., N.Y., N.C., Ohio, Oreg., Pa.,
Tenn., Tex., Va., W.Va., Wis.; Europe (Germany); Asia (Japan); Pacific
Islands (New Zealand). Ephemerum crassinervium var. papillosum (Austin) Renauld & Cardot has not been considered
worthy of recognition as a variety of E.
crassinervium (A. J. Grout 1935; V.
S. Bryan and L. E. Anderson 1957), a conclusion sustained by the present
studies. It was described originally because of its narrower leaves and a
strongly papillose calyptra, but both characters have been found to vary
independently. Ephemerum crassinervium
var. crassinervium shares several
characters with Ephemerum sessile
(Bruch & Schimper) K. J. A. Müller, a relatively common species in
Europe, the Mediterranean islands, and north Africa. It was reported as
occurring in North America (W. S. Sullivant 1856), and plants labeled Ephemerum sessile from “central Ohio” were
distributed by Sullivant and Lesquereux in 1856 as number 21 of Musci
Boreali-Americani. In 1933 A. J. Grout in Mosses of North America commented
that number 21 of Musci Boreali-Americani is not E. sessile, and I have
likewise found no North American plants that are convincingly E. sessile, as distinct from E. crassinervium.
3b. Ephemerum crassinervium var. texanum (Grout) V. S. Bryan & L.
E. Anderson, Bryologist 60: 73. 1957 Ephemerum
spinulosum var. texanum Grout, Moss Fl. N. Amer. 2:
70. 1935 Plants less than 2.2 mm. Leaves broadly lanceolate to oblong-lanceolate or ligulate and
acuminate, often narrowed distally from slight to prominent shoulders, (0.8--)1.3(--2.4) ´
(0.17--)0.23(--0.27) mm; margins serrate distal to the proximal third, often
with narrow shoulders bearing one or more teeth; apex acuminate, toothed, and
densely papillose in the distal half; costa thin at base, percurrent or
excurrent; areolation markedly dense distally; median laminal cells slightly
papillose; distal laminal cells densely papillose. Capsule with few stomates, scattered throughout. Spores various, commonly sub-globose,
(68--)78(--120) ´ (50--)66(--80) µm, dark brown. Capsules
mature year around, mostly in spring, autumn, and winter. Moist or drying soil,
frequently in old fields, on roadsides, or in mixed forests; 50--600 m; Ont.;
Ala., Ark., Fla., Ga., Ill., Ind., Iowa, Kans., La., Minn., Miss., N.J.,
N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Tex., W.Va. The variety texanum is distinguishable largely by
the dense papillosity of the distal half of the leaves. Secondarily, the
lanceolate leaf shape, modified by more or less evident shoulders at the base
of the acumen, confirms a determination. 4. Ephemerum spinulosum Bruch &
Schimper, Synop. Musc. Eur. 6. 1860 Phascum
serratum var. angustifolium Hooker & W. M.
Wilson ex T. Drummond, Musci Amer. (So. States) 2. 1841, in part; Ephemerum spinulosum var. hystrix (Lindberg) Grout Plants less than 2.5 mm, gregarious in
abundant, persistent, matted protonemata. Leaves setaceous to linear-lanceolate, (1.1--)2.0(--0.23) ´
(0.12--)0.17(--0.20) mm; margins serrate to strongly spinose; spines 40--60
µm, spreading or recurved to 45°; or
more, sometimes 2-celled; apex narrowly acuminate; costa occasionally lacking
in the proximal third, but usually strong, nearly 1/3 of the base, percurrent
or excurrent, spinulose or spinose; areolation firm proximally and denser
distally; median laminal cells in vertical rows, papillose or occasionally
smooth; distal laminal cells spinose. Capsule
with columella resorbed before meiosis; stomates few, mostly in the proximal
half. Spores spherical or
reniform, (58--)80(--118) ´ (42--)45(--80) µm. Capsules maturing
year around. Sides of ditches and ravines, moist paths, old fields, swamps,
moist or drying soil in disturbed, partly sunny areas, occasionally on
rotting wood; 5--700 m; Ont., Que., Sask.; Ala., Ark., Conn., Fla., Ga.,
Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss.,
Mo., Nebr., N.H., N.J., N.Y., N.C., Ohio, Pa., S.C., Tenn., Tex., Va., W.Va.,
Wis.; West Indies (Cuba), Central America (Honduras); South America (Brazil);
Europe; Asia (China, Japan, Taiwan). Ephemerum spinulosum bears, as part of the abundant and
persistent protonemata and rhizoids, red-brown, thick-walled structures. They
also occur occasionally in E. serratum,
but are only rarely seen in other Ephemera.
The cells may be long-lived vegetative diaspores, possibly a drought
tolerance mechanism (A. J. Grout 1928--1940; J. G. Duckett et al. 1993). As
in all species of Ephemeraceae, E.
spinulosum is polymorphous. Although rare, extreme expressions are found;
e.g., leaves rather broadly linear, an uncommonly thin costa, the marginal
dentation short---hardly more than the protruding distal ends of marginal
cells, and laxer areolation. When such extremes occur in combination, the
plants may approach E. crassinervium
var. crassinervium, Micromitrium wrightii, or M. tenerum, but other characters point
to the correct determination. This combination of traits exemplifies the
nature of variation found in the Ephemeraceae. OTHER
REFERENCES Bruch, P. and
W. P. Schimper. 1835. Laubmoose Europa’s in
Monographien. Phascum. Strassburg. Crum, H. A.
and L. E. Anderson. 1981. Mosses of Eastern North America. 2 vols. New York. Duckett, J.
G., J. A. Goode and A. D. Stead. 1993. Studies of protonemal morphogenesis in
mosses. I. Ephemerum. J. Bryol. 17:
397--408. Grout, A. J. 1928--1940.
Moss Flora of North America North of Mexico. 3 vols. Newfane, Vt. Hedwig, J.
1801. Species Muscorum Frondosorum. Leipzig. Ireland, R. R.
1982. Moss flora of the maritime provinces. Natl. Mus. Canada Publ. Bot.13. Ireland, R.
R., G. R. Brassard, W. S. Schofield and D. H. Vitt. 1987. Checklist of the
mosses of Canada II. Lindbergia 13: 1--62. Redfearn, P.
L. Jr. 1972. Mosses of the Interior Highlands of North America. Ann. Missouri
Bot. Garden 59: 1--104. Schofield, W.
B. 1968. A selectively annotated
checklist of British Columbia mosses. Syesis 1: 164--175. Sharp, A. J.,
H. A. Crum and P. M. Eckel, eds. 1994. Flora of Mexico. Vols. 1--2. Bronx,
New York. Sullivant, W.
S. 1856. The Musci and Hepaticae of the United States. In: A. Gray. Manual of
Botany, ed. 2. New York. Whitehouse, E. 1954. The mosses of Texas. Bryologist 57: 53--146. |
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Illustrations: Ephemerum cohaerens |
