AXTIIOPHYTA 359 



Family ol. Poaceae. Grasses, with 2-ranked leaves. 

 (Sp. about 3,o45.) 

 There aie six tril)es and several sub-tribes, of which the 

 Bamboos are the lowest, while the 

 Agrostideae, Paniceae and Maydeae 

 are at the summits 'of as many di- 

 verging phyletic lines. These groups 

 may be distinguished as follows: 



A. Woody })Iants; a joint between the leaf-blade and the 



sheath. 1. Bamboos. {Bambuseae) 

 Bambusa. 



B. Herbaceous plants; no joint between the leaf-blade 



and sheath. 



I. Spikelets with the larger flowers at the base. 



1. Spikelets typically containing several to many 



flowei's. 



a. IMostly arranged in panicles; awns ter- 



minal. 2. Fescue Grasses (Festuceae) 

 — Bromus. 



b. Arranged in panicles; awns dorsal. 2a. 



Oat Grasses (Avetieae) — Avena. 



c. Sessile in two rows on the opposite 



sides of the main stem. 2b. Wheat 

 Grasses ( Triticeae) — Triticum. 



d. Sessile in two rows on one side of a flat- 



tened axis. 2c. Gramma Grasses. 

 (Chlorideae) — Bouteloua. 



2. Spikelets containing but one flower. 3. Red- 



top Grasses (Agrostidcae) — Agrostis. 



II. Spikelets with the larger flowers at the top. 



1. A joint above the empty glumes. 



a. Spikelets with five glumes; palets one- 

 nerved. 4. Canary Grasses {Phal- 

 aridcae) — Phalaris. 



2. A joint below the empty glumes. 



a. Spikelets flattened laterally, one-flowered. 



4a. Rice Grasses (Oryzeae) — Oryza. 



b. Spikelets not flattened laterally, one to 



two-flowered. 

 (1) Stems hollow, medium sized to 

 small. 5. Panic Grasses {Paniceae)— 

 Panicum. 



