78 NORTH AMERICAN FLORA [VoLumME 17 
Spikelets upon distinct though sometimes short pedicels, 
arranged in open or contracted panicles, or in racemes: 
if in spikes, these are secund and the axis continuous and 
not notched for the reception of the spikelets. 
Spikelets not arranged in 2-rowed secund spikes. 
Spikelets 1-flowered. 
Empty scales 4, the palet 1-nerved. Tribe 7. PHALARIDEAE. 
Empty scales 2, or these sometimes wanting, the palet 
2-nerved. Tribe 8. AGROSTIDEAE. 
Spikelets 2-many-flowered. 
Flowering scales generally shorter than the empty 
ones, usually with a geniculate awn on the back or 
arising from between the teeth, rarely with a ter- 
minal awn or awnless. Tribe 9, AVENEAE. 
Flowering scales usually longer than the empty ones, 
awnless, or with a straight terminal, very rarely 
. dorsal, awn. Tribe 11. FESTUCEAE. 
Spikelets crowded in 2 close rows, forming 1-sided spikes 
or racemes with a continuous rachis. Tribe 10. CHLORIDEAE. 
Spikelets arranged in spikes, usually alternately in 2 opposite 
rows and equilateral, very rarely in 1 row and unilateral, 
the axis notched for the reception of the spikelets and some- 
times articulate. Tribe 12. HORDEAE. 
Stems woody, at least below; leaf-blades usually petiolate and 
articulated to the sheath, finally deciduous. Tribe 13. BAMBUSEAE. 
Tribe 1. MAYDEAE. ‘Tall monoecious grasses with pithy stems and broad 
flat leaf-blades. Spikelets unisexual, the staminate usually 2-, sometimes 1- 
flowered, arranged at the nodes commonly in pairs, one sessile, the other ped- 
icellate, or rarely both sessile or pedicellate, sometimes in 3’s, the pistillate 
generally 1-, sometimes 2-flowered, single at the rachis-nodes. Pistillate and 
staminate spikelets borne in separate inflorescences, the staminate in ter- 
minal panicles or racemes which have a continuous or tardily disarticulating 
rachis, the pistillate in fascicled spikes in the axils of the leaves, the rachis 
fragile and readily disarticulating, or the axes of the spikes sometimes grown 
together into a thick, spongy, cylindric, continuous, compound axis with the 
flowers borne in longitudinal rows; or the staminate and pistillate spikelets in 
different parts of the same inflorescence, the staminate occupying the upper 
part of it or of its divisions, the pistillate the lower. Grain of various shapes, 
not furrowed; embryo large; starch grains simple, polyhedral. Fruit com- 
pound, with the seeds naked, or rarely enclosed in large scales, arranged in 
several longitudinal rows; more frequently the grain is enclosed in a false 
fruit, consisting of the rachis internode and the attached parts, or of the in- 
durated sheath of the subtending leaf. 
Fruiting spikelets not enclosed in a hard ivory-like involucre, 
Staminate and pistillate spikelets in separate inflorescences, the former arranged in racemes in 
terminal panicles, the latter in axillary spikes subtended and enclosed by large basal bracts. 
Pistillate spikes separate, the rachis articulate. 1. EHUCHLAENA. 
Pistillate spikes grown together intoa thick spongy organ known asthe cob. 2. ZEA. 
Staminate and pistillate spikelets in the same inflorescence, the former occu- 
pying the upper and the latter the lower part of the spikes. 3. TRIPSACUM. 
Fruiting spikelets enclosed in a hard ivory-like ovoid or spheric involucre, formed 
of the sheath of the subtending leaf. 4, Cor. 
1. EUCHLAENA Schrad. Ind. Sem. Hort. Goetting. 1832. — 
Linnaea 8: Litt. 25. 1833. 
Reana Brign. Ind. Sem. Hort. Mutin. 1849. —Ann. Sci, Nat. III. 12: 365. 1849. 
Tall monoecious grasses, with usually long leaves, the staminate spikelets borne in 
racemes which are arranged in terminal corymbiform panicles, rarely single, the pistillate 
in fasciculate articulated spikes in the leaf-axils. Staminate spikelets in pairs, 2-flowered, 
unequally pedicellate ; scales 4, the outer 2 larger, membranous, empty, the inner 2 hya- 
line and enclosing each a flower; stamens3. Pistillate spikelets solitary, sessile, 1-flowered ; 
