150 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 
panicles. Species about 99, in the warm regions of both hemispheres, 
most abundant in America; 36 species in the United States. 
Type species: Agrostis indica L. 
Sporobolus R. Br., Prodr. Fl, Nov. Holl. 169. 1810. Three species are de- 
scribed, S. indicus, 8. elongatus, and S. pulchellus. Brown states that Sporobo- 
lus includes Agrostis species of Linneus. Of the three species described by 
Brown only the first was known to Linneus and included by him under Agrostis. 
Hence the first species is chosen as the type. 
Agrosticula Raddi, Agrost. Bras. 33, pl. 1, f. 2. 1823. Type A. muralis, the 
only species described. 
Bennetia Raf., Bull. Bot. Seringe 1: 220. 1830. Agrostis juncea Michx. is 
the only species included. This is Sporobolus gracilis. (Trin.) Merr. 
Crystostachys Steud., Syn. Pl. Glum. 1:.181. 1854. The type is C. vaginata, 
the only species described. From the description this appears to be Sporobolus 
vaginaeflorus. 
Bauchea Fourn., Mex. Pl. 2: 87. 1886. Type B. karwinskyi, the only species 
described. This is Sporobolus wrightii. 
The fruit is free from the lemma and palea, and falls readily from 
the spikelet at maturity. Because of this character the species have 
been called drop-seed grasses. The genus differs from Muhlenbergia 
in having 1-nerved awnless lemmas and from Agrostis in having 
lemmas as long as the glumes or longer and as firm. 
Four species of the United States are annual. One of them, 
Sporobolus vaginaeflorus (Torr.) Wood, is called poverty grass, 
because it grows in sterile soil. This has narrow panicles, partly or 
wholly inclosed in the sheaths. Several of the perennial species have 
creeping rhizomes. One of these, S. virginicus (L.) Kunth, is a 
common seashore grass in the Southern States. It has erect stems 
6 to 10 inches tall, with spikelike panicles of pale spikelets. The 
other species of the genus are erect bunch-grasses. Sporobolus ber- 
teroanus (Trin.) Hitche. and Chase (fig. 84), with long, slender, 
spikelike panicles, is common in the Southern States (S. indicus 
of the manuals, not S. indicus (L.) R. Br.). This: species is 
called smut-grass, because the inflorescence is frequently affected 
with a black fungus. The glumes are about equal and much 
shorter than the lemma. Sporobolus cryptandrus (Torr.) Gray 
(fig. 85) is common on sandy soil, especially in the interior of 
the country. This has very small spikelets in panicles sometimes 
partly inclosed in the upper sheath, only the upper portion 
spreading, or even entirely inclosed in the swollen sheaths. There 
is a conspicuous tuft of hairs at the summit of the sheaths. In 
winter the leaves and stems become fibrous and much frayed out by 
the wind. 
Two species of the Southwest are important forage grasses in the 
arid and semiarid regions. Sporobolus airoides Torr. (fig. 86), 
growing in dense, tough clumps, the stems 1 or 2 feet high, and with 
large spreading panicles, is found on somewhat alkaline soil and is 
called bunch-grass or alkali saccaton. It ranges from Nebraska to 
