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BFNA Title: Amblystegiaceae |
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XX. Amblystegiaceae G. Roth Lars
Hedenäs Plants
small, medium-sized, or large; green, yellowish, or brownish. Stem distichously branched, sometimes
almost unbranched; cortex of small and incrassate
cells; hyalodermis present or not; pseudoparaphyllia mostly foliose, the outer occasionally filamentose; paraphyllia absent
or present; rhizoids red-brown, smooth or warty-papillose, slightly or
strongly branched; rhizoids or rhizoid initials on stem at or just below leaf
insertions or from lower back of costa,
occasionally from leaf lamina near leaf apex (Conardia); axillary
hairs mostly well developed. Stem
leaves straight or falcate (gradually curved) or squarrose,
plicate or smooth; costa single and mostly long, or
double and usually short; median lamina cells linear or short-linear, rarely
rectangular or hexagonal, 1-stratose or sometimes
partially 2- or multistratose, smooth or rarely
prorate or papillose; alar cells differentiated or
not, sometimes inflated. Inner perichaetial leaves straight and erect, lanceolate or ovate or oblong or slightly obovate, plicate or rarely smooth; costa
usually well developed, single or double; vaginula
with paraphyses. Seta long or rarely short, smooth. Capsule cylindric or short-cylindric, curved and horizontal to
straight and erect, stomata long-pored; annulus separating or not; operculum conic
or rarely rostrate or short-rostrate. Peristome perfect
or specialized; perfect exostomes yellow-brown or
brownish, cross-striolate or sometimes reticulate
on outer surface below, papillose distally, with dentate or slightly dentate
margin and an exostome border ± widened at zone of transition in outer peristomial layer pattern; specialized exostome teeth
variously narrow or short, sometimes with outer surface basally papillose; perfect
endostomes with high basal membrane, segments long
and not or narrow-perforate, cilia nodose or
sometimes appendiculate; specialized endostomes with basal membrane ± reduced or sometimes
absent, cilia short to absent, segments narrower and sometimes shorter than
in perfect endostomes. Calyptra cucullate, smooth. Genera
20--30, species 100--150 (18 genera, XXX species in the flora): temperate to
sub-polar regions worldwide, tropical mountains. The Amblystegiaceae
as here circumscribed, excluding the Calliergonaceae,
include several genera or species groups that may not belong to or are even unlikely
to belong to this family in a strict sense. These include Calliergonella, Campylophyllum, Conardia, Donrichardsia, most of Hygrohypnum, Platylomella, Sanionia, and Tomentypnum. At the moment, however,
knowledge of the relationships of these taxa is
still limited, and they are therefore included with the Amblystegiaceae.
The genus Amblystegium
is here understood in a wide sense, including Hygroamblystegium, but
excluding Serpoleskea (here treated in Platydictya). Members of the Amblystegiaceae
are sometimes confused with those of other pleurocarpous
families, such as the Brachytheciaceae and Plagiotheciaceae. Most members of the Brachytheciaceae
and Plagiotheciaceae differ from those of the Amblystegiaceae in their non-plicate and often recurved rather than plicate and erect inner perichaetial leaves (in species with horizontal capsules).
In the Brachytheciaceae horizontal capsules are swollen
rather than cylindric, the stomata round-pored rather than long-pored, and
the exostome base is mostly red or brown-red rather than yellow-brown. The exostome
teeth borders are gradually narrowed upwards rather than suddenly widened where
the outside pattern of the teeth changes from cross-striolate
to papillose, the endostome segments are widely rather than narrowly perforate,
and the spores mature in the winter rather than the summer half of the year in
temperate areas. Plagiotheciaceae members have pale
whitish yellow exostomes and, in addition, differ
from the Amblystegiaceae in several diagnostic gametophyte
features, including rhizoid position and ornamentation, and branching mode
(see Platydictya
treatment). On the other hand, the morphological differences between members
of the Amblystegiaceae s. str.
and those of other families, such as the Hypnaceae
and Thuidiaceae, or the sometimes segregated or recognized
Campyliaceae, Cratoneuraceae,
Donrichardsiaceae, and Helodiaceae,
are more diffuse. Differences between the Amblystegiaceae
and the Calliergonaceae are discussed under the
latter. SELECTED REFERENCES Hedenäs, L. 2003. Amblystegiaceae
(Musci). Flora Neotropica,
Monograph 89: 1--107. Hedenäs, L. and A.
Vanderpoorten. 2007. The Amblystegiaceae and Calliergonaceae. In: A. E. Newton and R. Tangney, eds. Pleurocarpous Mosses: Systematics and Evolution. The
Systematics Association Special Volume Series 71, pp. 163--176. Vanderpoorten,
A., B. Goffinet, L. Hedenäs, C. Cox, and A. J. Shaw.
2003. A taxonomic reassessment of the Vittiaceae (Hypnales, Bryopsida): evidence
from phylogenetic analyses of combined chloroplast
and nuclear sequence data. Plant Syst. Evol. 241: 1--12. Vanderpoorten, A., L. Hedenäs, C. Cox,
and A. J. Shaw. 2002. Phylogeny and morphological evolution of the Amblystegiaceae (Bryopsida). Molec. Phylog. Evol. 23: 1--21. Vanderpoorten, A., L. Hedenäs, C. Cox,
and A. J. Shaw. 2002. Circumscription, classification, and taxonomy of Amblystegiaceae (Bryopsida) inferred
from nuclear and chloroplast DNA sequence data and morphology. Taxon 51: 115--122. 1. Leaves with wide 2--5-stratose border or intramarginal
band of rectangular or linear cells, sometimes 1-stratose
near leaf base and leaf apex. 2.
Leaves with 2--4-stratose marginal border; margin
denticulate; plants creeping, irregularly to subpinnately
branched...................................................................................................... 18.
Platylomella,
p. xx 2.
Leaves with 2--5-stratose intramarginal
band; margin dentate; plants dendroid. 1. Leaves without
clearly differentiated multistratose border or intramarginal band. 3.
Stem with at least a partial hyalodermis. 4.
Stem leaves plicate or strongly so; costa single
and long....................................... 12.
Sanionia,
p. xx 4.
Stem leaves smooth; costa single and long, or short
and double. 5.
Species in or close to running water or lake shores; costa
in most leaves either single and long, double or branched and ending in
mid-leaf, or short and double; when short and double median leaf lamina cells
27.5--66 \um .............................. 3.
Hygrohypnum (in part), p. xx 5.
Species in various wet and humid habitats; costa
short and double; median leaf lamina cells 42--115(--145) \um........................................................................................ 14.
Calliergonella,
p. xx 3.
Stem without hyalodermis. 6.
Alar cells of stem leaves not differentiated from
other basal cells; costa single. 7.
Large, golden yellow plants with strongly plicate leaves; leaf apex longly acuminate; often with numerous, strongly branched
rhizoids from proximal abaxial surface of costa......... 13.
Tomentypnum,
p. xx 7.
Small, green or brownish plants with smooth leaves; leaf
apex acuminate or blunt; rhizoids sparsely branched, never from abaxial surface of costa. 6.
Alar cells of stem leaves more or less differentiated,
small or inflated, sharply or diffusely delimited from surrounding cells; costa single or double. 8.
Stem leaves at most 1 mm. 9.
Rhizoids or rhizoid initials present on abaxial
surface of costa or on lamina near leaf apex;
rhizoids warty-papillose and often strongly branched, then forming tomentum...................................................................................................................... 15.
Conardia,
p. xx 9.
Rhizoids or rhizoid initials only on stem or at abaxial
costa insertion, never on leaves; rhizoids smooth
or rarely granular-papillose, slightly to strongly branched, rarely forming tomentum. 10.
Stem leaves from erect to spreading base recurved
or squarrose, at least along some shoot portions;
acumen when differentiated distinctly furrowed. 11.
Stem leaf costa short and double, often ending in a
spine on back of leaf; scattered distal lamina cells usually distally prorate
on dorsal side, at least in some branch leaves; seta relatively short, 8--22
mm. 12. Most or many leaves with clearly differentiated
acumen; leaf apex acuminate or narrowly so........................................ 16.
Campylophyllum,
p. xx 12. Leaf acumen not differentiated; leaf apex acute or
blunt. 11.
Stem leaf costa long and single, or sometimes
shorter and double in some (rarely all) leaves, not ending in a spine on back
of leaf; distal lamina cells smooth; seta often long, 12--45 mm. 13. Largest cells in proximal half of alar
group in stem leaves 18--25 \um wide; paraphyllia
often present, narrow-lanceolate to ovate-lanceolate; autoicous; endostome
cilia nodose. 13. Largest cells in proximal half of alar
group in stem leaves 10.5--19(--21) \um wide; paraphyllia
absent; dioicous; endostome cilia nodose or partially appendiculate............................................................. 6.
Campyliadelphus,
p. xx 10.
Stem leaves variously straight or falcate, but not recurved
to squarrose; acumen plane or almost so. 14.
Plants submerged in brooks and rivers, sometimes on irrigated rocks; leaves almost
orbicular, broadly ovate, or ovate; in the latter case stem leaves either
with broadly rounded apex or alar groups well
differentiated. 3. Hygrohypnum, p. xx 14.
Plants terrestrial (sometimes on shores). Leaves varying around ovate; leaf
apex acuminate, if blunt with alar cells weakly
differentiated from other basal cells. 15. Costa double and short....................................................... 4.
Platydictya,
p. xx 15.
Costa single and long. 16. Spore capsule straight and erect; operculum
short-rostrate; exostome teeth short, papillose throughout; endostome lacking
basal membrane and cilia; plants usually
growing as epiphytes on trees, sometimes on rotten wood.............................................................. 5.
Anacamptodon,
p. xx 16. Spore capsule curved and horizontal; operculum conic;
exostome well developed, teeth cross-striolate
basally; endostome with basal membrane, cilia mostly well developed; plants
of various habitats..... 11. Amblystegium (in part), p. xx 8.
Stem leaves longer than 1 mm. 17.
Stem leaves from erect to spreading base recurved
or squarrose, at least along some shoot portions;
acumen distinctly furrowed. 18.
Stem leaves to 1.7 mm; alar cells slightly
inflated, widest alar cells 10.5--17.5(--21) \um wide.................................................................................. 6.
Campyliadelphus,
p. xx 18.
Stem leaves at least 1.6 mm; alar cells strongly
inflated, widest alar cells 17--31.5 \um wide. 19. Stem leaf costa double
and short; alar cells forming an ovate or
rectangular group along basal margin of leaf, extending from leaf margin 28--33%
of distance to leaf middle at insertion; dioicous. 19. Stem leaf costa single
and long, or often double and short in at least some leaves; alar cells forming a transverse-triangular group,
extending from leaf margin 67--100% of distance to leaf middle at insertion; autoicous................... 9.
Drepanocladus (in part), p. xx 17.
Stem leaves variously straight or falcate, but not recurved
to squarrose; acumen plane or furrowed. 20.
Paraphyllia present on stem, occasionally rare and
visible only in youngest shoot portion; rhizoids stem-borne, often forming tomentum. 21.
Stem leaves plicate; at least some median lamina cells usually prorate or
papillose abaxially; paraphyllia
linear or lanceolate-linear. 21.
Stem leaves smooth; median lamina cells smooth; paraphyllia
± lanceolate..... 1. Cratoneuron, p. xx 20.
Paraphyllia absent; rhizoids rarely forming tomentum; when much branched usually inserted on proximal
abaxial surface of costa. 22.
Stem leaf costa double or forked, short or ending
up to mid-leaf or slightly above. 23. Alar cells quadrate to
long-rectangular, more or less strongly incrassate, inflated or slightly
inflated; alar group indistinctly delimited, large,
transverse-triangular; axillary hairs early yellow
or brownish.................... 10.
Pseudocalliergon,
p. xx 23. Alar cells and alar group different; axillary
hairs hyaline when young........ 3.
Hygrohypnum
(in part), p. xx 22.
Stem leaf costa single and long. 24.
Alar cells of stem leaves distinctly delimited from
surrounding cells. 25.
Alar cells not or slightly inflated; frequently in
streams or on wet rocks........................................................................ 3.
Hygrohypnum (in part), p. xx 25.
Alar cells strongly inflatedl;
usually in other wet habitats than running water........................................................... 9.
Drepanocladus (in part), p. xx 24.
Alar cells of stem leaves gradually delimited from
surrounding cells. 26. Rhizoids or rhizoid initials present abaxially on costa or on lamina
near leaf apex; rhizoids warty-papillose and strongly branched, often forming
tomentum........................................................... 15.
Conardia,
p. xx 26.
Rhizoids or rhizoid initials only on stem or abaxially
on costal insertion, never on leaves; rhizoids smooth, slightly to strongly branched, rarely forming tomentum. 27.
Alar cells of stem leaves
mostly incrassate to strongly so, rarely thin-walled in mature leaves; axillary hairs well developed, abundant, with early
yellowish or brownish distal cells. 27.
Alar cells of stem leaves thin-walled or slightly
incrassate in mature leaves; axillary hairs well
developed and abundant or small, delicate and sparse, with young distal cells
hyaline. 28.
Leaf apex rounded or blunt; costa ending 1/2--3/4
way up leaf; plants submerged in brooks and rivers, sometimes on irrigated
rocks................................................ 3.
Hygrohypnum (in part), p. xx 28.
Leaf apex acuminate; if blunt or obtuse then costa
ending in or just before apex; plants of various habitats, sometimes
submerged. 29.
Stem leaf costa ending
60--75% of way up leaf, (45--) 52.5--114 \um wide near base; median lamina
cells 42--117 \um.... 8. Leptodictyum, p. xx 29.
Stem leaf costa ending in distal acumen to percurrent, or ending somewhat farther down in acumen (in
latter case, 29.5--58(--77.5) \um wide
near base); median lamina cells (9--)13--65(--67) \um. |