Grimmia attenuata

(Müller Hal. & Kindberg) Kindberg

Eur. N. Amer. Bryin. 2: 228. 1898,.

Basionym: Racomitrium alternuatum Müller Hal. & Kindberg in J. Macoun and N. C. Kindberg, Cat. Canad. Pl., Musci, 73. 1892
Treatment appears in FNA Volume 27. Treatment on page 249. Mentioned on page 206, 228, 247.

Plants robust, brownish to reddish in distal part, black and frequently defoliated proximally. Stems 5–10 cm, central strand absent. Leaves straight appressed when dry, erectopatent when moist, lanceolate, 2.7–3.5 × 0.5–0.75 mm, sharply keeled distally, margins narrowly reflexed on both sides, awns terete, firm and short, denticulate, costa 70-120 µm wide at base, channeled distally, circular, projecting on dorsal side; basal juxtacostal laminal cells elongate with extremely thick, slightly nodulose walls; basal marginal laminal cells in a few rows short-rectangular, thin-walled; medial laminal cells short to long-rectangular with extremely thick and sinuose lateral walls; distal laminal cells 1-stratose, apex and margins 2-stratose. Gemmae absent. Sexual condition dioicous. Seta cygneous, 3–4 mm. Capsule sporadically present, exserted, yellowish-brown, ovoid, smooth, exothecial cells thin-walled with incrassate corners, annulus present, operculum rostrate, peristome teeth orange, 40–60 µm wide at base, split and perforated, smooth proximally, papillose distally. Calyptra not seen.

Habitat: Loose tufts on dry boulders
Elevation: low to moderate elevations (0-1000 m)


V27 342-distribution-map.gif

B.C., Alaska, Idaho, Wash.


Of conservation concern.

Grimmia attenuata resembles forms of the extremely variable Racomitrium heterostichum (= Bucklandiella heterosticha), and because G. N. Jones (1933) mentioned five varieties of the latter, it is not surprising that in some herbaria, e.g. NY, all specimens of G. attenuata have been filed as varieties of R. heterostichum. In 1898, Kindberg realized that his species is not a Racomitrium, but a Grimmia, and wrote: “Habit of G. elatior.” In spite of Kindberg’s correct transfer to Grimmia, T. C. Frye (1917–1918) synonymized G. attenuata with R. macounii. Adding to the confusion, H. A. Möller (1929) synonymized it with G. elatior, and J. Muñoz (1999b) cited it as G. arcuatifolia, which is a synonym of G. lisae. Grimmia elatior is characterized by ellipsoid striate capsules, leaf margin broadly recurved on just one side, and an opaque 2-stratose distal lamina with rounded usually mammillose to papillose cells, the mid leaf cells quadrate to short-rectangular with slightly sinuose, thick walls. Like Grimmia leibergii, G. attenuata is characterized by its elongate to linear, strongly nodulose and thick-walled basal juxtacostal cells, its extremely thick-walled and sinuouse medial cells, leaf margins both recurved, and stem central strand absent. However, the two differ in costa shape and basal marginal cell shape.

Selected References


Lower Taxa


"thick" is not a number.

... more about "Grimmia attenuata"
deciduous +  and persistent +
well-defined +
differentiated +
Roxanne I. Hastings +  and Henk C. Greven +
(Müller Hal. & Kindberg) Kindberg +
only rarely longer +
not papillose +
denticulate +  and terete +
sinuous +  and straight to sometimes +
sinuose-nodulose;quadrate;elongate +
oblate;elongate +
divided +
Racomitrium alternuatum +
undifferentiated +
plicate +  and smooth +
less +  and 1/2 +
not papillose +
mitrate +  and cucullate +
small;medium +
yellowish-brown +
pendulous +  and cernuous +
striate +  and smooth +
thin +  and thick +
thick-walled +  and thin-walled +
quadrate +  and rectangular +
incrassate +
excurrent;percurrent;excurrent +
subpercurrent +
channeled +
usually not markedly larger +
70um +  and 120um +
1-stratose +  and multistratose +
2-stratose +  and 1-stratose +
2-stratose +  and 1-stratose +
B.C. +, Alaska +, Idaho +  and Wash. +
low to moderate elevations (0-1000 m) +
reproduction +  and asexual +
dioicous +  and sexual +
Loose tufts on dry boulders +
papillose +, mammillose +  and smooth +
specialized +
dioicous +, autoicous +  and sexual +
straight +
2.7mm;3.5mm +
keeled +  and lanceolate +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.075 cm0.75 mm <br />7.5e-4 m <br />) +
1;multistratose +
thick-walled +  and sinuose +
thick-walled +  and sinuose +
not +  and enlarged +
not +  and differentiated +
lanceolate;linear +
Eur. N. Amer. Bryin. +
short-rectangular +
straight +
sigmoid +  and arcuate +
papillose +  and smooth +
cygneous +
short to long +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
papillose +
globose +
5 cm50 mm <br />0.05 m <br /> (10 cm100 mm <br />0.1 m <br />) +
muticous;long-awned +
Dryptodon +  and Hydrogrimmia +
Grimmia attenuata +
Grimmia subg. Rhabdogrimmia +
species +
nodulose +
black;brownish;reddish +