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California Moss eFlora

Jan 1 2013 ·

Home · List of Genera · Key to Keys · Accepted Names · Synonyms · For Beginners · Subdivisions of CA · Jepson eFlora for CA Vascular Plants
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Dicranella (C. Müller Hal.) W. P. Schimper, 1856.



Dicranella is a group of largely soil inhabiting mosses, abundant mostly in the humid northwest regions of the state. The leaves are generally falcate-secund. In the field the large Dicranum of logs, tree bases and soil is easily distinguished from the markedly smaller Dicranella. Sporophytic plants are always good to have for effective identification, but gametophytes without sporophytes are usually identifiable.

Key to Dicranella Etc.

Mosses treated in this section are acrocarpous and costate mosses with the subulate leaves often falcate-secund. The majority of the species have plane to erect margins but a few are recurved. All have abaxial and adaxial stereid bands in the costa, and most have bistratose streaks and/or margins in a leaf cross-section.

Species included in this key are all in Dicranaceae:
Cynodontium jenneri (W. P. Schimper in Howie) Stirton
Cynodontium strumulosum C. Müller Hal. & Kindberg in Macoun, not known from CA
Cynodontium tenellum (Bruch & W. P. Schimper) Limpricht
Dicranella crispa (Hedwig) W. P. Schimper
Dicranella grevilleana (Bridel) W. P. Schimper, recognized from CA since 2004
Dicranella heteromalla (Hedwig) W. P. Schimper
Dicranella hilariana (Montagne) Mitten
Dicranella howei Renauld & Cardot
Dicranella pacifica W. B. Schofield
Dicranella palustris (Dickson) Crundwell ex Warburg
Dicranella rufescens (Withering) W. P. Schimper
Dicranella schreberiana (Hedwig) Hilferty
Dicranella subulata (Hedwig) W. P. Schimper
Dicranella varia (Hedwig) W. P. Schimper, recognized from CA since 2004

A. Leaf squarrose from a strongly sheathing base .....B
A. Leaf base not abruptly expanded and sheathing .....E

B. Leaf base only gradually contracted to the lanceolate limb; leaf apex broadly obtuse to rounded .....Dicranella palustris
B. Leaf base abruptly contracted to the subulate limb with the shoulders defining nearly a 45 angle relative to the costa; leaf apex narrowly obtuse to acute .....C

C. Capsule erect and sulcate; distal portion of subula 2-3 cells thick, not well-differentiated in cross-section from the costa .....Dicranella crispa
C. Capsule inclined, sulcate or not; distal portion of subula mostly unistratose except for the margin .....D

D. Leaves distally denticulate; many of the cells at mid-leaf more than 10 µm wide; capsules sulcate when dry .....Dicranella grevilleana
D. Leaves entire or nearly so to the apex; cells at mid-leaf about 5 µm wide; capsules smooth when dry .....Dicranella schreberiana

E. Plant crispate when dry; leaf margins recurved .....F
E. Plant not crispate; leaf margins incurved or recurved and bistratose .....H

F. Median leaf cells papillose or papillose on high mammillae; leaf margins unistratose .....Cynodontium: C. strumulosum not known from CA
F. Median leaf cells smooth or mammillose .....G

G. Leaf margins unistratose; perigonium with acute bracts; median leaf cells mostly more than 12 µm wide .....Cynodontium: C. jenneri
G. Leaf margins bistratose; perigonium with obtuse bracts; median leaf cells mostly less than 10 µm wide .....Cynodontium: C. tenellum

H. Vegetative leaves lanceolate to narrowly lanceolate, with the lamina at mid-leaf mostly more than 10 cells wide on each side of the costa; leaf margins recurved at least near the base .....I
H. Vegetative leaves subulate above the middle with the lamina mostly more narrow; leaf margins plane to incurved, mostly unistratose .....L

I. Leaves bluntly rounded or obtuse at apex with margins unistratose .....Dicranella hilariana
I. Leaves acute to narrowly subulate at apex with margins bistratose .....J

J. Costa broad, occupying about 1/3 of the leaf base; guide cells present on adaxial surface in costa cross-section; leaf margin only minutely recurved near the base; lateral walls of the exothecial cells somewhat sinuose, not much thicker than the transverse walls .....Dicranella howei
J. Costa occupying up to 1/4 of leaf base; guide cells not adaxially exposed; leaf margin recurved to mid-leaf; lateral walls of the exothecial cells nearly straight, about twice as thick as the associated transverse walls .....K

K. Upper leaves to 2 mm long; leaf cells near the apex mostly two or more times as long as broad .....Dicranella varia
K. Upper leaves more than 3 mm long; leaf cells near the apex mostly less than twice as long as broad .....Dicranella pacifica

L. Seta yellow, even when old; mouth of capsule oblique when dry and deoperculate; spores nearly smooth .....Dicranella heteromalla
L. Seta becoming red-brown to purple at maturity; mouth of capsule not oblique; spores finely papillose .....M

M. Capsule erect or nearly so, symmetric; annulus wanting .....Dicranella rufescens
M. Capsule inclined to horizontal, asymmetric; annulus well developed, of two rows of cells .....Dicranella subulata


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