Heterocladium macounii
Pterigynandraceae
Macoun's bileaf moss, Macoun's heterocladium moss
with epidermal cells distinctly multipapillose.
erect to ± creeping, freely and irregularly branched to subpinnate;
paraphyllia few or absent;
pseudoparaphyllia foliose.
erect-appressed when dry, erect when moist;
stem leaves to 1 mm;
margins papillose-serrate;
apex acute to short-acuminate;
costa single and frequently 2-fid or double to mid leaf;
laminal cells papillose, papillae 2–4 per lumen.
erect to erect-spreading or occasionally squarrose, often homomallous, usually imbricate, concave, stem leaves often somewhat larger than branch leaves;
margins entire, serrulate, or subentire;
apex usually acuminate; ecostate or costa single, double, or 2-fid, short or to mid leaf;
alar cells not or weakly differentiated;
medial laminal cells quadrate, rhomboidal, or oblong-rhomboidal, smooth or papillose.
dioicous.
erect or horizontal, short-cylindric;
operculum short-rostrate or conic, cucullate;
peristome double.
Heterocladium macounii
Pterigynandraceae
Heterocladium macounii grows almost exclusively on rock throughout its range and is only rarely collected on the other substrates frequented by the other two North American species. In the field, H. macounii can be difficult to separate from H. dimorphum, but the small, distinct stem papillae and multiple laminal cell papillae are good distinguishing traits of the former. There have been observations that H. macounii grows exclusively on rock; though this is generally the case, a few collection labels mention soil over rock or humus. Displaying a classic Arcto-Tertiary disjunct distribution reported for some bryophytes, the species is found in North America in the southeastern and northwestern United States and Alaska. Recently it has also been reported at high elevations in Mexico and El Salvador.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Genera 6, species 28 (4 genera, 8 species in the flora).
Five of the genera of Pterigynandraceae are restricted to the Northern Hemisphere, including all genera found in the flora area. The one exception, Trachyphyllum A. Gepp, is widely distributed in tropical and subtropical areas throughout Africa, central parts of South America, and southern Asia.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Leaf apices long-piliferous; ecostate or occasionally costae double, short; margins entire. | Iwatsukiella |
1. Leaf apices obtuse, acute, apiculate, or acuminate; costae single, double, or 2-fid, short, to mid leaf, or almost ecostate; margins serrulate, serrate, or dentate | → 2 |
2. Leaves oblong-elliptic; laminal cells oblong-rhombic, prorulose; capsules erect. | Pterigynandrum |
2. Leaves ovate to broadly ovate; laminal cells quadrate or rhomboidal, papillose, prorulose, or smooth; capsules erect to horizontal | → 3 |
3. Costae single, short, usually 2-fid, or double to mid leaf; capsules horizontal, short- cylindric, curved. | Heterocladium |
3. Costae short, usually double or indistinct; capsules erect to nearly horizontal, cylindric, symmetric. | Myurella |
BC
CalFlora
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
