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BFNA Title: Dacryophyllum |
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DACRYOPHYLLUM
- Hypnaceae
XXX. DACRYOPHYLLUM Ireland, Novon 14: 70. 2004. * [Greek dakryo-, to shed tears or weep, and phyllon, leaf, alluding to the basal leaf cells having proximal
prorulae with the appearance of tears] Robert R. Ireland Plants small, in thin mats,
complanate-foliate, glossy, light- to yellow-green. Stems
prostrate, relatively short
and narrow, simple or sparingly and irregularly branched, cortical cells
moderately small, thick-walled, in 2--3 rows, central cells large,
thin-walled, central strand lacking; rhizoids few, smooth, on ventral surface
of stems and branches, single or in clusters just proximal to leaf insertion;
axillary hairs ca. 108 /um, mainly in axils of distal leaves near apical bud, with 1
short, brown basal cell and 1--2 elongate, hyaline distal cells;
pseudoparaphyllia narrowly foliose, 2--4 cells wide, margins serrulate to
toothed, sometimes with single-celled, large teeth, usually mixed with some
entire filamentous pseudoparaphyllia, 3--6 cells in length, branch primordium
not evident among pseudoparaphyllia. Stem and branch leaves similar,
stiff, appressed-imbricate, flat, smooth, asymmetric, oblong-lanceolate,
acute to obtuse, falcate, margins plane, serrulate, becoming serrate at leaf
base, serrations often formed by two abutting basal cell, broadly incurved on
one side at base, nondecurrent; costa lacking or indistinctly double; cells
thin to moderately thick-walled, linear-flexuose to rhomboidal, especially
near leaf apex, smooth or often with minute prorulae on abaxial surface at
distal and proximal ends, prorulae sometimes more prominent on basal cells,
with walls not pitted; basal row of cells at stem insertion each with a large
prorula at proximal end on abaxial surface; alar regions differentiated, 1--4 rows of
quadrate to rectangular cells with 2--7 cells in marginal row. Specialized
asexual reproduction lacking. Sexual condition unknown. Species 1;
western North America. Dacryophyllum is endemic to California, occurring in
the west-central part of the state in terrestrial habitats on calcareous
substrates in Coast Redwood forests. SELECTED
REFERENCES. Ireland, R. R. 2004.
Dacryophyllum falcifolium, a new North American
genus and species (Musci: Hypnaceae) from California. Novon 14: 70--74. Kellman, K. and J. R. Shevock. 2006.
Notes on Dacryophyllum falcifolium Ireland. Evansia 23: 36--39. Norris, D. H. and J. R.
Shevock. 2004. Contributions toward a bryoflora of
California: I. A specimen-based catalogue of mosses. Madroño 51: 1--131. Norris, D. H. and J. R. Shevock. 2004. Contributions toward a bryoflora of
California: II. A key to the mosses. Madroño 51: 133--269. 1. Dacryophyllum falcifolium Ireland, Novon 14: 70. 2004
Stems to 1.5 cm, 0.8--1 mm wide. Leaves
0.3--0.5 × 0.1--0.2 mm; median cells 32--45 × 4--5 /um; apical cells 10--28 x
5--7 /um; alar cells 8--19 x 6--7 /um.
Sexual condition unknown,
neither antheridia nor archegonia seen.
Vertical
surfaces of shaded, calcareous rock cliffs and rock outcrops in redwood
forests; 50--240 m; Calif. (Monterey and Santa Cruz counties). Dacryophyllum falcifolium
is macroscopically distinguished by small-sized plants, the stems prostrate,
only ca. 1.5 cm; small complanate-foliate, glossy leaves that are light- to
yellow-green; usually strongly falcate leaves with acute to obtuse apices;
and serrulate to serrate leaf margins.
Microscopically, it is recognized by its costa, which is lacking or
indistinct or short and double; alar region that has abutting cells along the
margins forming serrations; prorulae on the abaxial surface of the leaf cells
often at both ends; basal row of leaf cells at the stem juncture where there
are large prorulae at the proximal ends on the adaxial surface; and
pseudoparaphyllia that are foliose with serrulate to toothed on the margins,
sometimes mixed with entire filamentous ones. The genus Dacryophyllum appears most closely
related to Taxiphyllum, another
genus in the Hypnaceae that occurs on calcareous substrates, but it differs
from all species in that genus primarily because they lack the large prorulae
on the abaxial surface at the proximal ends of the basal cells at the stem
insertion. The genus also differs by
filamentous, entire pseudoparaphyllia occuring in clusters mixed with
foliose, serrulate to toothed ones without an evident branch primordium. In Taxiphyllum,
on the other hand, the branch primordia are nearly always evident and the
species only have foliose pseudoparaphyllia.
Although no specialized asexual reproductive bodies are known for Dacryophyllum falcifolium, K. Kellman and J. R. Shevock (2006) have observed
that small branches break off the plants and the thin mats of the species are
easily removed from the substrate.
They therefore believe that these branches may be easily moved from
place to place by small animals or strong winds, as asexual reproduction. |
