|John R. Reeder|
Plants perennial; cespitose, essentially
glabrous throughout. Culms 30-130 cm. Sheaths open; ligules
of hairs; micro hairsof blades with an inflated terminal cell similar in
length to the basal cell. Inflorescences terminal, narrow, spikelike or
somewhat open panicles; disarticulation above the glumes but not between
the florets, these falling together. Spikelets with 3-5 florets, only the
lower 1-3 bisexual. Glumes subequal, thin, membranous, 1-veined, acute;
lemmas rounded on the back, hairy at least basally, obscurely (5)7(9)-veined,
veins extending into scabridulous awns of unequal length, several additional narrow
awnlike lobes usually also present, awns and lobes together forming a pappuslike
crown; paleas textured like the lemmas, 2-veined, 2-keeled, keels scabrous
or hairy; anthers 3; styles 2. Caryopses elliptical, plump,
slightly dorsally flattened or nearly terete; embryos about 1/2 as long
as the caryopses. x = 10. From the Greek pappos, pappus, and phoros,
bearing, in reference to the pappuslike crown of the lemma.
Pappophorum is an American genus with about eight species. It grows in warm regions of North and South America. There are two species native to the Flora region.
Panicles purple-tinged, narrow, but usually with some slightly spreading branches; lemma bodies 3-4 mm, the awns mostly not more than 1.5 times as long, these rarely spreading at right angles ..... 1. P. bicolor
Panicles white or tawny, rarely slightly purplish, tightly contracted; lemma bodies 3-3.2 mm, the awns about twice as long, commonly spreading at right angles when mature ..... 2. P. vaginatum
1. Pappophorum bicolor E. Fourn.
Culms 30-80(100) cm. Sheaths mostly glabrous, apices with a tuft of hairs on either side; ligules about 1 mm; blades 10-20(30) cm long, 2-5 mm wide, flat to involute. Panicles 12-20 cm, narrow but usually with some slightly spreading branches, pink- or purple-tinged. Spikelets with the lower 2 or 3 florets bisexual, distal 1-2 florets sterile. Glumes 3-4 mm, thin, glabrous, apices acute or minutely notched and mucronate; lemmas somewhat firm, usually faintly 7-veined, with 11-15 awns; lowest lemma bodies 3-4 mm, midveins and margins pubescent from the base to about midlength, awns about 1.5 times as long as the lemma bodies; paleas subequal to the lemma bodies or slightly longer. Caryopses about 2 mm. 2n = 100.
Pappophorum bicolor grows in open valleys, road right of ways, and grassy plains in Texas and northern Mexico. A report for Arizona (Mearns 1175) was apparently due to mixed labels. There have been no subsequent reports of the species from the state.
2. Pappophorum vaginatum Buckley
Culms (40)50-100 cm. Sheaths mostly glabrous, with a tuft of hairs at the throat; blades 10-25 cm long, 2-5 mm wide, flat to involute, adaxial surfaces scabridulous. Panicles 10-25 cm, tightly contracted, usually white or tawny, rarely slightly purple-tinged. Spikelets with 1(2) bisexual florets and 2 reduced florets. Glumes (3)4-4.5 mm, glabrous, acute; lowest lemma bodies 3-3.2 mm, midveins and margins pubescent from the base to about midlength, awns about twice as long as the lemma bodies, tending to spread at right angles when mature; paleas longer than the lemma bodies. 2n = 60.
Pappophorum vaginatum grows in similar habitats to P. bicolor, the two species sometimes growing together. Its range extends from southern Arizona to Texas and northern Mexico and from Uruguay to Argentina.