Plants perennial; cespitose, not rhizomatous. Culms 15-250 cm, often disarticulating at the first node, basal internodes persistent, often swollen and clavate. Leaves mostly basal; ligules of hairs; blades flat or convolute, eventually disarticulating from the sheaths. Inflorescences terminal, panicles, not plumose. Spikelets laterally compressed, with (1)2-5 florets; rachilla prolonged beyond the distal florets, terminating in a rudimentary floret, internodes 1/3-1/2 as long as the florets, glabrous; disarticulation beneath the florets. Glumes exceeded by the florets, 1- or 3-veined; calluses 0.1-0.3 mm, blunt, glabrous or sparsely strigose, hairs to 0.5 mm; lemmas glabrous, inconspicuously 3(5)-veined, rounded over the back, acute to obtuse, unawned; paleas subequal to the lemmas; anthers 3. Caryopses falling free from the lemmas and paleas; pericarps loosely adherent. x = 9. Named for Juan Ignazio Molina (1740-1829), a Jesuit missionary and botanist, and the author of the first comprehensive summary of Chilean plants.

Molinia is a genus of two to five species, all of which are native to temperate Eurasia. One species is established in the Flora region.

1.   Molinia caerulea (L.) Moench
Purple Moorgrass, Molinie Bleue

Culms 15-150(250) cm, erect, rigid; basal internodes 2-6 cm, usually swollen and clavate. Collars marked with a line or narrow ridge; sheaths smooth, mostly glabrous, margins sparsely hairy distally; blades 0.2-1 cm wide. Panicles 5-40 cm, usually contracted; branches short and erect or long and lax. Spikelets 4-9 mm. Lower glumes 1.5-2.5 mm, hyaline, obtuse, slightly erose; upper glumes 2-3 mm, acute; calluses completely or almost glabrous; lemmas 2.5-4.5 mm, ovate, acute to obtuse; anthers 1.5-3 mm, purple. 2n = 18, 36, 90.

Molinia caerulea is established at scattered locations in the Flora region, but not at all the locations where it has been found. For instance, the record for Pennsylvania reflects a collection made in 1945 from an abandoned field; there are no extant populations known in the area. Most records are from southeastern Canada and the northeastern United States, but it has also been reported as being established in western Oregon.

Plants with long, lax panicle branches have been called Molinia caerulea subsp. arundinacea (Schrank) H. Paul rather than M. caerulea (L.) Moench subsp. caerulea, but there are many intermediates.