8 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 



Spikelets in pairs, one sessile and perfect, the other pedicellate and 

 usually staminate or neuter (the pedicellate one sometimes 

 obsolete, rarely both pedicellate) ; lemmas hyaline. 



13. Andropogoneae (p. 1252). 



DESCRIPTIONS OF THE TRIBES AND KEYS TO THE GENERA. 



TRIBE 1, BAMBOSEAE. 



The tribe which includes the bamboos is for the most part confined 

 to the Tropics and Subtropics. One genus extends into the southern 

 United States. The bamboos have woody jointed, usually holloAV 

 culms either erect or vinelike. Some of the larger kinds are as much 

 as a foot in diameter and, 100 feet in height. The common economic 

 species of the Tropics, such as Bambos vulgaris Schrad. (Banibos 

 bambos (L.) Wight), because of the large hollow culms with hard 

 partitions at the nodes found in most large species, can be 

 used for a great variety of purposes. Many kinds of bamboos 

 are cultivated for ornament in the warmer parts of the United States, 

 especially in Florida and California. Arundinaria japonica Sieb. 

 and Zucc. with several-flowered spikelets, and a few species of Phyl- 

 lostachys, are hardy as far north as Washington. They form dense 

 masses of shoots, usually 8 to 20 feet high. Phyllost achys does not 

 usually flower in this country, but the plants can be distinguished by 

 the internodes which are flattened on one side. Bambusa is a modi- 

 fied spelling of the original Bambos. 



TRIBE 2, FESTUCEAE. 



Spikelets more than 1-flowered, usually several-flowered, in open, 

 narrow, or sometimes spikelike panicles; lemmas awnless or awned 

 from the tip, rarely from between the teeth of a bifid apex ; rachilla 

 usually disarticulating above the glumes and between the florets. 



A large and important tribe, mainly inhabitants of the cooler 

 regions. The lemma is divided into several awns in Pappophorum 

 and its allies, is 'deeply 2-lobed In Triplasis and in a few species of 

 Triodia, 3-lobed in Blepharidachne, several-toothed in Orcuttia, and 

 slightly 2 -toothed in Bromus and a few other genera, the awn, when 

 single, arising from between the teeth. The paleas are persistent 

 upon the continuous rachilla in most species of Eragrostis. Sclero- 

 pogon, Monanthochloe, Distichlis, and a few species of Poa and 

 Eragrostis are dioecious. Gynerium, Cortaderia, Arundo, and Phrag- 

 mites are tall reeds. In Blepharidachne there is a pair of sterile 

 florets at the base of the single fertile floret, and a rudiment above. 

 In some species of Melica there is, above the fertile florets, a club- 

 shaped rudiment consisting of one or more sterile lemmas. In Uniola 

 there arc one to four sterile lemmas below the fertile ones. In Melica 

 imperfecta and M. torreyana there may be but one perfect floret. 



