146 POACEAE 
dry, the uppermost one much exceeding the inflorescence: inflorescence included at the 
base, the exserted portion 12 em. long or less, its branches erect, the larger 5-7 cm. long: 
spikelets about 1 cm. long ; scales 8-10, the lower empty ones acuminate, usually awned or 
awn-pointed, the flowering scales, exclusive of the awn, 4.5-5 mm. long, acuminate at the 
2-toothed apex, the nerves pilose below the middle, the lateral ones usually slightly excur- 
rent, the awn $ as long as the scale-body or more. [Leptochloa polystachya Chapm. ] 
In brackish marshes, New York to South Carolina. Summer and fall. 
5. Diplachne Halei Nash. Stems 6-10 dm. tall, finally branched: leaf-sheaths 
smooth ; blades erect or ascending, 1.5-4 dm. long, 6-12 mm. wide, flat, very rough : in- 
florescence finally exserted, 2-3 dm. long, 4-10 em. wide, its numerous branches ascending, 
4-7 cm. long: spikelets 4-6 mm. long, about 2 mm. wide; scales 7-10, the lower empty 
ones rough, the first scale acute, the second obtuse, the flowering scales about 3 mm. long, 
slightly and usually obtusely 2-toothed at the obtuse apex, the lateral nerves pilose toward 
the base, not excurrent, the midnerve glabrous or pilose toward the base, excurrent in an 
awn 0.2 mm. long or less. 
In marshes, Louisiana to Texas. Summer and fall. 
6. Diplachne dubia (H.B.K.) Benth. Stems tufted, 3-10 dm. tall, simple: leaf- 
sheaths smooth ; blades erect, smooth or rough, 2-8 mm. wide, the uppermost one 1.5-8 
em. long, the lower 1.5-4 dm. long: inflorescence usually finally exserted, 1-2 dm. long, 
the 5-20 racemes erect to spreading, the larger 5-11 cm. long: spikelets 5-9 mm. long ; 
scales 5-10, the lower empty ones acuminate, the flowering scales about 4.5 mm. long, ob- 
long, rough at the 2-lobed apex, the lobes rounded at the summit, the nerves glabrous, the 
lateral ones vanishing considerably below the apex of the Iobes, the midnerve at the cleft 
or rarely extending into a short awn, the margins of the scale pilose below the middle. 
In woods and rocky places, Florida to Texas, Arizona and Mexieo. Summer and fall. 
102. RHOMBOLYTRUM Link. 
Perennial grasses, with usually flat leaf-blades and a narrow contracted spike-like 
panicle. Spikelets numerous, several-flowered. Scales several ; 2 lower empty, 1-nerved ; 
flowering scales broad, rounded at the summit, 3-nerved, the nerves glabrous, the lateral 
ones disappearing below the margin, the midnerve at the margin or sometimes excurren 
as a short projection. Stamens 3. Styles short, distinct. Stigmas plumose. 
1. Rhombolytrum albéscens (Munro) Nash. Stems 2-6 dm. tall: leaf-sheaths 
shorter than the internodes; blades ascending, 0.5-2 dm. long, 2-5 mm. wide, smooth : 
panicle contracted, spike-like, 6-15 cm. long, 8-15 mm. broad, its branchés short and 
appressed : spikelets 4.5-5 mm. long, about 2.5 mm. wide, oval; scales 8-10, the 2 outer 
empty ones rather broad, 1-nerved, the flowering scales about 3 mm. long, nearly orbicular 
when spread out, rounded at the erose and sometimes acuminately 2-toothed apex, 3- 
nerved, the nerves glabrous, the lateral ones vanishing below the margin, the midnerve at 
the margin or sometimes excurrent as a short projection. 
In dry gravelly soil, Texas to Arizona. Summer. 
103. ERAGRÓSTIS Beauv. 
Low or tall annual or perennial tufted rarely dioecious grasses, the stems sometimes 
prostrate or creeping, with flat or convolute leaf-blades and open or contracted panicles. 
Spikelets numerous, arranged singly or in fascicles, 2-many-flowered, the flowers perfect or 
unisexual. Scales 4- many, membranous, compressed, keeled, the 2 lower empty, unequal, 
the remaining scales larger, 3-nerved, obtuse or acute at the apex ; palet shorter than the 
scale, prominently 2-nerved or 2-keeled, often incurved and persistent on the rachilla after 
the fall of the scale. Stamens 2 or 3. Styles distinct, short. Stigmas plumose. 
A. Stems not creeping: flowers perfect. 
a. Palet of the spikelets glabrous on the keels or merely hispidulous. 
* Annuals. 
Spikelets 2-5-flowered. 
hene and branches of the paniele short: stems usually branehed 
above. 
Pedicels and branches of the diffuse panicle long and capillary : stems 
branched only at the base. 
Stems slender, rarely equalling 5dm. in height : leaf-blades usually 
1.5 dm. long or less. 2. E. capillaris. 
Stems stout, 8-12 dm. tall: leaf-blades elongated, 4-6 dm. long. 3. E. hirsuta. 
Spikelets more than 5-flowered. : 
Panicle narrow, elongated, 2.5-5 dm. long, its branches erect or nearly 
so: spikelets crowded. 4. E. glomerata. 
1. E. Frankii. 
