Part 2, 1912] POACEAE 99 
19. ARTHRAXON Beauv. Agrost. 111. 1812. 
Pleuroplitis Trin, Fund. Agrost. 174. 1820. 
Lucaea Kunth, Rév. Gram. 489. 1831. 
Batratherum Nees, Edinb. New Phil. Jour. 18: 180. 1835. 
Lasiolytrum Steud. Flora 29: 18. 1846. 
Pstlopogon Hochst.; A. Rich. Tent. Fl. Abyss. 2: 447, 1852. Not Pstlopogon Hochst. 1846. 
Alectoridia A. Rich. Tent, Fl. Abyss. 2: 447. 1852. 
Usually low slender creeping grasses, with broad cordate-clasping leaf-blades, and with 
racemes or spikes aggregated at the summit of the stem or its branches. Racemes or spikes 
2-many, unequal, the rachis often somewhat flexuous, the internodes filiform. Spikelets 
usually in pairs at each node of the rachis, one pedicellate, the other sessile. Sessile spikelet 
lanceolate or linear, often a little oblique, 1-flowered, the flower hermaphrodite; first scale 
with the margins not or but little folded; second scale keeled, sometimes with a small mucro; 
third scale hyaline, empty; fourth scale hyaline, entire or slightly 2-toothed, with usually a 
slender perfect or rarely imperfect awn arising from the back above the base; palet minute or 
wanting. Stamens 2 or 3. Stigmas longer than the styles, exserted near the base of the 
spikelet, rarely included. Grain linear, somewhat terete. Pedicellate spikelet awnless, 
usually empty, rarely with a staminate flower, or entirely wanting. 
Type species, Arthraxon ciliaris Beauv. 
1. Arthraxon Quartinianus (A. Rich.) Nash. 
Alectoridia Quartiniana A. Rich. Tent. Fl. Abyss. 2: 448. 1852. 
Arthraxon ciliaris Quartinianus Hack. in DC. Monog. Phan. 6: 356. 1889. 
Stems slender, barbed at the nodes, otherwise glabrous, finally decumbent at the base 
and rooting at the nodes, the upright portions up to 3 dm. long; leaf-sheaths glabrous or 
papillose-pilose; blades 2-5 cm. long and 1 cm. wide or less, ovate-lanceolate, acuminate, 
cordate and clasping at the base, more or less pilose on both surfaces; spikes few to many, 
2-3 cm. long, the internodes pilose with long erect hairs; spikelets 3-5 mm. long, the first 
scale usually hispid toward the apex. 
TYPE LOCALITY: Near Adowa, Abyssinia. 
DISTRIBUTION : Introduced into Jamaica and Guadeloupe. Native of Africa and Asia. 
ILLUSTRATION: A. Rich. Tent. Fl. Abyss. pi. 99. 
20. DIECTOMIS H. & B.; Beauv. Agrost. 132, 150, 160. 1812. 
Homoeatherum Nees; H. & A. Bot. Beech. Voy. 239. 1836. 
Perennial grasses with flat or complanate leaf-blades, and 1-several spike-like racemes borne 
at the apex of the stem and its branches. Rachis of many internodes which, when separated, 
are crowned with an irregular cup-shaped toothed appendage. Spikelets in pairs. Sessile 
spikelet much compressed laterally; first scale 2-keeled, infolded on the margins; second 
scale much broader than the first, bearing below the apex a long imperfect awn; third scale 
hyaline, infolded on the margins; fourth scale membranous, 2-toothed, a stout perfect awn 
arising from between the teeth; palet shorter than the scale, subtending a perfect flower. 
Stamens 3. Styles short, as long as the stigmas, which are exserted below the middle of the 
spikelet. Pedicellate spikelet flowerless, broad, twice as long as and differing much in form 
from the sessile spikelet and concealing it, the first scale awned. 
Type species, Andropogon fastigiatus Sw. 
Raceme 1; intercarinal space of the first scale of the sessile spikelet pilose above. 1. D. fastigiata. 
Racemes 2-4; intercarinal space of the first scale of the sessile spikelet glabrous. 2. D. laxa. 
1. Diectomis fastigiata (Sw.) Beauv. Agrost. 150, 160. 1812. 
Andropogon fastigiatus Sw. Prodr. 26. 1788. 
Pollinia fastigiata Spreng. Pugill, 2:13. 1815. 
Andropogon Hochsiettert Steud. Syn. Gram. 384. 1854. 
Heteropogon Hochstetteri Schweint. Beitr. Fl. Aeth. 310. 1867. 
Sorgum fastigiatum Kuntze, Rev. Gen. 791. 1891. 
Stems up to 1 m. tall, branched, the branches in 1’s-3’s; leaf-sheaths loose, keeled; ligules 
5-10 mm. long, broader than the leaf-blades; blades of the innovations up to 3 dm, long, 1-4 
