HITCHCOCK AND CHASE—-NORTH AMERICAN PANICUM. 99 
Panicum caricoides Nees,“ the type specimen of which, in the Munich Herbarium, 
was collected by Martius in the province of Para, Brazil, is an allied species. The 
Martius specimen differs from the West Indian plants in having larger spikelets, 1.8 
to 1.9 mm. long, and numerous long, stiff, erect hairs on the pedicels. 
DISTRIBUTION. 
Borders of ponds and wet savannas, Costa Rica and the West Indies; also in Brazil. 
Costa Rica: Buenos Aires, Pittier 10589. 
Cusa: Herradura, Baker & Dimmeck 4837 (Hitchcock Herb.), Hitchcock 155; 
without locality, Wright 3871; Hanabana, Wright 192 (Grisebach Herb.). 
Santo Dominco: Wright, Parry, é Brummel 624. 
Brazit: Prov. of St. Paul, St. Hilaire 758 (Paris Herb.); Barra, Spruce 1289 (Gray 
Herb.). 
Agrostoidia.—Tufted perennials; culms erect, compressed, sheaths more or less 
keeled; ligules membranaceous, short, sometimes ciliate; blades long and 
narrow; spikelets lanceolate, glabrous; first glume keeled, scabrous on the 
keel toward the apex, the second glume and sterile lemma pointed beyond 
the fruit, more or less keeled, the spikelet thus often appearing laterally 
compressed, the palea of the sterile floret about half as long as its lemma; 
fruit elliptic, smooth and shining, a minute tuft of thickish hairs at the apex. 
The first three species of this group have much the appearance of certain 
species of Agrostis. 
Rootstocks present; culms but little compressed; spikelets set 
obliquely on their appressed pedicels. 
Panicles open; spikelets 3.4 to 3.8 mm. long (shorter in 
exceptional specimens).................2-------- 55. P. anceps. 
Panicles more or less contracted; spikelets not over 2.8 
mm. long.........--...2. 2200-222 e eee bee eee eee 56. P. rhizomatum. 
Rootstocks absent; culms strongly compressed with keeled 
sheaths; spikelets not obliquely disposed. 
Ligules ciliate; basal leaves half as long as the culm or 
more; panicle much exceeding the upper leaves. 
Spikelets not over 2.7 mm., usually 2.5 mm. long, the 
first glume less than half that length; ligules 2 
to 3mm. long. ........2..2-0--.........0.2--. 53. 2. 
Spikelets 3 to 3.5 mm. long; first glume two-thirds to 
three-fourths that length; ligule less than 1 
mm. long...........-...-22-----22222-2200-- 54. P. combsit. 
Ligules erose or lacerate, not ciliate; basal leaves in short 
tufts, the upper usually nearly equaling the terminal 
longifolium. 
panicle. 
Fruit stipitate; spikelets 2.5 to 2.8 mm. long, con- 
spicuously secund....................2.-..-- 52. P. stipitatum. 
Fruit not stipitate; spikelets not conspicuously se- 
cund. 
Spikelets 1.8 to 2 mm., in occasional specimens 
2.2 mm. long; panicle branches ascending 
or spreading........-----...-.--.------- 50. P. agrostoides. 
Spikelets about 2.5 mm. long; panicle branches 
erect or nearly s0.................-.---- 51. P. condensum. 
2 Nees in Trin. Gram, Pan. 149. 1826; Nees, Agrost. Bras. 108. 1829. 
