GENERA OF GRASSES OF THE UNITED STATES. 281 
and on opposite sides at each joint of the thick, hard articulate lower 
part of the same rachis, sunken in hollows in the joints, consisting of 
one perfect floret and a sterile lemma ; first glume coriaceous, nearly 
infolding the spikelet, fitting into and closing the hollow of the 
rachis; second glume similar to the first but smaller, infolding the 
remainder of the spikelet; sterile lemma, fertile lemma, and palea 
ver}^ thin and hyaline, these progressively smaller. 
Robust perennial grasses, with usually broad flat blades and 
monoecious terminal and axillary inflorescences of 1 to 3 spikes, the 
pistillate part below, breaking up into bony, seedlike joints, the 
staminate above on the same rachis, deciduous as a whole. Species 
about seven, all American, extending from the middle United States 
to northern South America ; three species in the United States. 
Type species : Coix dactyloides L. 
Tripsacum L., Syst. Nat., ed. 10, 2 : 1261. 1759. Type the first of the two 
species described, T. dactyloides, based on Coix dactyloides L., and T. hermaph- 
roditum. The second species, based on " Cenchrus 2, Brown. Jam. 367," is 
now referred to Anthephora. 
Dactylodes Zanoni-Monti ; Kuntze, Rev. Gen. PI. 2 : 772. 1891. Two species 
are included, D. angulatum, based on Coix angulatus Mill., and D. fasciculatum, 
based on Tripsacum fasciculatum Trin. Coix angulatus, which is the same as 
Tripsacum dactyloides, is taken as the type. 
The common species in the United States is Tripsacum dactyloides 
(PI. XX; fig. 170), a robust perennial, 3 to 6 feet tall, with broad 
blades, the terminal spikes mostly in threes, the axillary spikes mostly 
solitary. This species, called gama grass, is found in moist places 
from Connecticut to Texas and Florida. It is a good forage grass, 
but is usually not abundant enough to be of much importance. A 
second species, T. floridanum Porter, with narrow blades, is found in 
southern Florida, and a third species, T. lemmoni Vasey, with pilose 
lower sheaths, is found in Arizona. 
142. Euchlaena Schrad. 
Staminate spikelets as in Zea; pistillate spikelets single, on oppo- 
site sides, sunken in cavities in the hardened joints of an obliquely 
articulate rachis, the indurate first glume covering the cavity ; sec- 
ond glume membranaceous, the lemmas hyaline. Spikes infolded in 
foliaceous bracts or husks, 2 to several of these together inclosed in 
the leaf sheaths. 
The one species generally recognized is Euchlaena mexicana 
Schrad., a tall annual with somewhat the aspect of corn {Zea mays), 
a native of Mexico. 
Type species : Euchlaena mexicana Schrad. 
Euchlaena Schrad., Ind. Sem. Hort. Goettingen. 1832. Only one species 
described. The specimen was collected by Dr. Miihlenfordt in Mexico. 
The genus is little known. Several species have been proposed, 
but they are doubtfully distinct from Euchlaena mexicana. An un- 
