BOTANY. 69 
rachis, forming a solitary spike. Glumes horizontal, often side by side in the 
same plane, sometimes deficient. Palez, either pointless or the lower some- 
times tipped with a straight awn or bristle. 
The principal genera are Hordeum, Secale, Triticum. Hordeum vulgare 
and disticum constitute common barley. Rye is Secale cereale, and the com- 
mon wheat is Triticum vulgare. 
Tribe 4. Festucacee. Spikelets several- (few- or many-) flowered, panicled, 
the uppermost flower often imperfect or abortive. Paleze pointless, or the 
lower sometimes tipped with a straight (not twisted nor deeply dorsal) awn or 
bristle. Stamens one to three. Squamulee two. 
The common cheat, or chess, Bromus secalinus, belongs to this tribe. 
Also, the orchard-grass, Dactylis glomerata; Rattlesnake-grass, Glyceria 
canadensis ; meadow or spear grass, Poa annua and pratensis; Blue grass, 
or Wire grass, Poa compressa. False red-top grass, Poa serotina; Fescue 
grass, Festuca elatior and pratensis. The bamboo, Bambusa arundinacea, is 
represented in pl. 55, fig. 10. 
Tribe 5. Avenacee. Spikelets two, several-flowered, panicled, the terminal 
flower mostly imperfect. Glumes and pales, thin and membranaceous, or 
chartaceous, the lower palea bearing a twisted or bent awn on the back. Sta- 
mens three. Squamulz two. 
The common oat, Avena sativa, the skinless oat, A. nuda, and the Hair- 
grass, Aira czespitosa and flexuosa, belong to this tribe. 
Tribe 6. Chloridee. Spikelets (rarely one-flowered) usually several-flowered, 
with the upper flowers imperfect, disposed in one-sided spikes. Glumes per- 
sistent, the upper one looking outward. Rachis or axis jointless. Spikes 
usually racemed or digitate. Stamens two or three. 
Here belong the Cord grass, Spartina cynosuroides, and other well-known 
species of Spartina; the crab grass, Eleusine indica, and the Bermuda grass, 
Cynodon dactylon. 
Tribe 7. Pappophoree. Spikelets two, many-flowered. Superior flowers 
abortive. ‘Two glumes and two paleze. membranaceo-herbaceous. Lower palea, 
' three, meltifid, the divisions subulate awned. The principal genera are Am- 
phipogon, Diplopogon, Triraphis, Pappophorum, Cottea, &c. 
Tribe 8. Arundinacee. Spikelets sometimes unifloral with or without 
the pedicel of a superior flower, sometimes wmultifloral. Flowers most 
frequently covered or surrounded at their base with long, soft hairs, two 
glumes and two membranaceo-herbaceous palez, the glumes often equal or 
superior to the flowers in length, the inferior palea awned or pointless. 
Plants generally elevated. 
Tribe 9. Agrostidee. Spikelets flowered, perfect, sometimes with the 
abortive pedicel or rudiment of a second flower above, panicled, or the panicle 
sometimes contracted into a dense cylindrical spike or head. Stamens not 
more than three. 
Here belong the fox-tail grasses, Alopecurus; Timothy grass, or Herds’ 
grass of New England, Phleum pratense; Rush grass, Vilfa; Bent grass, 
Agrostis ; Red-top, or Herds’ grass of Pennsylvania, A. vulgaris; &e. 
Tribe 10. Panicee. Spikelets two-flowered; inferior flower incomplete. 
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