Poa sect. Madropoa
Plants perennial; densely to loosely tufted or with solitary shoots, sometimes stoloniferous, sometimes rhizomatous. Basal branching intra- and/or extravaginal. Culms (5)10-125 cm, terete or weakly compressed; nodes terete or slightly compressed. Sheaths closed from 1/7 their length to their entire length, terete to compressed, smooth or scabrous, glabrous or pubescent; ligules 0.2-18 mm, milky white or colorless, usually translucent, truncate to acuminate, glabrous or ciliolate; innovation blades with the adaxial surfaces usually moderately to densely scabrous or hispidulous on and between the veins, sometimes smooth and glabrous; cauline blades flat, folded, or involute, thin or thick, lax or straight, smooth or scabrous, adaxial surfaces sometimes hairy, apices narrowly to broadly prow-shaped. Panicles 1-29 cm, contracted to open, usually with fewer than 100 spikelets; nodes with 1-5 branches; branches 0.5-18 cm, terete or angled, smooth or scabrous, glabrous or hispidulous. Spikelets 3-17 mm, lengths 3.5 times widths, laterally compressed, not sexually dimorphic, not bulbiferous; florets 2-10(13) mm, normal; rachilla internodes smooth or scabrous, glabrous or hairy. Glumes distinctly keeled, keels smooth or scabrous; lower glumes 1, 3(or 5)-veined; upper glumes 3- or 5-veined; calluses terete or slightly laterally compressed, glabrous, webbed, or with a crown of hairs; lemmas 2.6-11 mm, lanceolate, distinctly keeled, keels, veins, and intercostal regions glabrous or hairy, 5-7(11)-veined; palea keels scabrous, glabrous or with hairs at midlength; anthers 3, vestigial (0.1-0.2 mm) or 1.3-4.5(5) mm.
Discussion
Poa sect. Madropoa is confined to North America. Its 20 species exhibit breeding systems ranging from sequential gynomonoecy to gynodioecy and dioecy. The gynomonoecious species usually grow in forests and have broad, flat leaves. The gynomonoecious and dioecious species grow mainly in more open habitats. They have normally developed anthers that are 1.3-4 mm long, and involute innovation blades that, in several species, are densely scabrous or hairy on the adaxial surfaces.
There are two subsections in the Flora region: subsects. Madropoa and Epiles.
Selected References
None.