GRASS FAMILY. 





66 / 

 



68. < 

 upper Male* empty 



i iota. 



Flowering scale of some other structure. 



Flowering scales i- 3 -nerved, all with perfect flowera, or the uppermost with a 



staminate flower only or empty. 

 Panicle branches spirally arranged. 



Panicle branches simple, in spike-like rac< 6t DifiUtkme 



Branches of the panicle mostly again divided 



Spikelets loosely 2-4-flowered; conical r.u lull.i 



r, , '!/ 



Spikelets densely 2-7o-flowered; rachilla not articulated, linfe or 



throat of sheath bearded. 



Primary branches of the panicle distichous, usually branched anin at thr > ~irr 

 Panicle spike-like or much contract' 



Second scale broader than the _ flowering one*. 

 Second scale not broader than the \ 7 flo\ 

 Panicle diffuse, with long slender brain h 

 Flowering scales 3-many-ncrvcd, with 2 or more of the 



appressed, convolute around each other. 

 Stamens 3; upper sterile scales usually club shaped. 

 Stamens 1-2; sterile scales not club shaped. 

 Flowering scales 5-rnany-nerved, each with a perfect llowt-r, or the upper MMBctiow* 



abortive. 



Keel of the palet winged or with a linear appendage. 

 Keel of the palet not appendaged. 



Scales more or less strongly compressed and k< 

 Empty basal scales 3-6: spikelets flat 

 Empty basal scales 2; spikelets flattened. 

 Panicle contracted; spikelets dioecious. 

 Panicle open; spikelets perfect. 



Flowering scales herbaceous, awn pointed, p-.; ctrd 



in one-sided clusters. 

 Flowering scales scarious-margined; rachis glabruun or with 



webby hairs. 

 Spikelets large, cordate. 

 Spikelets mostly smaller, not co: 



Empty scales projecting In-yond the uppcrmort flower- 

 ing- ones; arctic grass. 

 Uppermost scales exceeding the empty one*; flowering 



scales 2-10, mostly webby at bast- 

 Flowering scales membranous; rachis h:- -tiff hair*. 

 extended into a hairy appendage. 80. Grapkefikotum 

 Scales rounded on the back, at least below. 



Stigmas placed at or near the apex of the < 



Flowering scales with a basal ring of hairs, prominently - nerved. 



toothed at apex; water gi 79. SctHoekioa. 



Flowering scales naked at the 1 



Obtuse or subacute and -carious at the apex, run: 

 Plainly 5-7-nerved : -ivies prc-cnt 

 Obscurely 5-nerved; no style or 

 Acute, pointed or awned at apex; not webby. >; 

 Stigmas plainly arising below the apex of the ovary; pikelrt 

 usually drooping; scales mostly awned 84. Bromitt. 



Tribe XI. HORDE AE. 



Stigma i; spike unilateral; spikelets i-flowered, narrow. 

 Stigmas 2; spike symmetrical. 



Spikelets solitary at the notches of the rachis. 



Flowering scales with their backs turned to the rachis. 

 Flowering scales with their sides turned to the rachis. 

 Spikelets i-2-flowered in slender articulate spikes. 

 Spikelets a-many-flowered in stout inarticulate spikes. 

 Spikelets 2-6 at each joint of the rachis; scales mostly long-awm d. 

 Spikelets i-flowered or with the rudiment of a second flov. 

 Spikelets 2-many-flowered. 



Empty scales a little smaller than the flowering ones. 

 Empty scales very small or none. 



Tribe XII. BAMBUSKAK. 



Tall canes with large flat spikelets in panicles or racemes. 



i. TRIPSACUM L. Syst. Ed. 10, 2: 1261. 

 [DIGITARIA Heist.; Adans. Fam. PL : 38. 



Tall perennial grasses with thick rootstocks, rather broad Hat leave 

 flowers. Spikelets i-2-flowered, in terminal or axillary, solitary c 

 spikes. Staminate spikelets in 2 's at each node of the axis, a- 

 scales, the two outer coriaceous, the two in jer thinner, the palet byal 

 tillate spikelets in excavations at the lower joints of the spike, i-flowere 

 style slender. Grain partly enclosed in the excavations of the spikes, co, 

 hornv exterior lower scale. [Name from the Greek, in allusion to the pol. 



About 3 species, natives of tropical and temperate America, 

 occurs in the southern United States. 



'Jut. 



86. Lolimm 



- i 



89. 



: !( 



.,1 //. 



