ANTHOPHYTA 359 



Family 31. Poaceae. Grassesj with 2-raiiked leaves. 

 (Sp. about 3,545.) 

 There are six tribes 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 plants; 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 



flowers. 



a. Mostly arranged in panicles; awns ter- 



minal. 2. Fescue Grasses (Festuceae) 

 ■ — Bromus. 



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



Oat Grasses (Aveneae) — 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 (Agrostideae) — 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- 

 arideae) — -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 hoUow, medium sized to 

 small. 5. Panic Grasses (Paniceae) — 

 Panicum. 



