Polypogon viridis |
Polypogon |
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water beardgrass |
beardgrass, rabbitsfoot grass |
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Habit | Plants perennial, often flowering the first year, 10–90 cm tall. | Plants annual or perennial, 4–120 cm tall, not rhizomatous. |
Culms | rooting at the lower nodes, branched near the base. |
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Leaves | sheaths glabrous; smooth; ligules to 5 mm; blades 2–13 cm × 1–6 mm. |
sheaths open; ligules membranous or hyaline; erose, ciliate; blades flat to convolute. |
Inflorescences | ovoid-oblong to pyramidal, interrupted, 2–10 cm; pedicels not developed; stipes 0.1–0.6 mm. |
dense panicles, continuous or interrupted below; disarticulation at the base of the stipe. |
Spikelets | borne on a stipe connected to a pedicel or directly to the panicle branch, laterally compressed, 1 floret; rachilla not prolonged beyond the floret. |
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Glumes | 1.5–2 mm, scabrous on the back and keel; tips obtuse to truncate; awnless. |
lanceolate, 2; longer than the floret, bases not fused; tips entire to emarginate or bilobed, usually awned; glume awns arising from between the lobes, sometimes at the tip, curved, glabrous. |
Caryopses | slightly flattened, broadly ellipsoid to oblong-ellipsoid. |
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Lemmas | approximately 1 mm; tips erose; awnless. |
1–3(5)-veined, often awned; lemma awns terminal, subterminal, or arising from just above mid-length. |
Anthers | 0.3–0.5 mm. |
3. |
Paleas | 33% to as long as the lemmas. |
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2n | =28. |
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Polypogon viridis |
Polypogon |
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Distribution | ||
Discussion | Mesic stream banks, rivers, ditches. 0–100m. Col, WV. CA, NV, WA; north to British Columbia, southeast to TX; Eurasia. Exotic. This small grass resembles an Agrostis with unusually scabrous glumes, but its spikelets disarticulate below the glumes. Unlike other Polypogon species, it lacks glume awns. It has been collected from two sites along the Columbia River. |
Tropical and warm-temperate regions worldwide. Approximately 18 species; 4 species treated in Flora. Polypogon species resemble Agrostis but have strongly scabrous, usually awned glumes that are supported on a stipe. Polypogon occasionally hybridizes with Agrostis. The hybrids look like Agrostis, but the spikelets disarticulate below the glumes, often at the base of a stipe. Polypogon fugax was collected in Portland in the early 1900s but apparently has not persisted. It is an annual with glume awns similar to P. interruptus, but its glumes have lobes 0.1–0.2 mm. |
Source | Flora of Oregon, volume 1, page 470 Barbara Wilson, Richard Brainerd, Nick Otting |
Flora of Oregon, volume 1, page 469 Barbara Wilson, Richard Brainerd, Nick Otting |
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | Agrostis semiverticillata, Agrostis verticillata | |
Web links |
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