TRIANDRIA. 13 



10. PIIALARIS. Cal. of two rather unequal valves containing a dou- 

 ble corolla. Seed* invested with the inner hardened corolla. 



1 1. PHLEUM. Cal. of 2 valves, valves nearly equal, acuminate 

 dr inucronato-aristate, including a single awnless corolla. 

 Seed free. 



12. MILIUM. Cal. of 2 valves, valves ventricose. Seed invested 

 with the permanent hardened corolla. 



13. AGROSTIS. Cal. of 2 valves, valves acute, compressed, awn- 

 less. Cor. shorter than the calyx, slightly hairy at the base. 

 Seed free. 



14. ARUNDO. Cal. of 2 valves (in A. Pfiragmiles many-fl.). 

 Cor. surrounded with long hairs. Seed free covered with the 

 corolla. 



31. ROTTBOLLIA. Cal. of 2 valves, valves lateral. Flowers alter- 

 nate, ranged upon a jointed rachis. 



*t"f Flowers polygamous. 



30. HORDEUM. Cal. in threes, 2-valved, valves lateral, inter- 

 mediate ones perfect ; lateral ones with Anthers or Pistil. Cor. 

 2-valved, awned. 



** Calyces 2- or rarely 3- flowered , 

 f Flowers perfect. 



17. AIRA. Cal. of 2 valves, unequal. Cor. 2-valved, the outer 

 one awned above the base (rarely awnless). Florets without 

 any imperfect ones between them. Seed free, but covered with 

 the Cor. 



18. MELICA. Cal. of 2 valves, about 2 flowered, with the ru- 

 diment of a third floret. Cor. 2-valved, awnless. Seed free, 

 covered by the cartilaginous Cor. 



ft Flowers polygamous. 



15. HOLCUS. Cal. of 2 valves, 2-flowered. Cor. 2-valved. 

 Anther '-bearing floret awned. Seed free, or enveloped in the 

 membranaceous Cor, 



16. HiEROCHLOEf. Cal. of 2 valves, 3-flowered. Cor. of 2 

 valves: the lateral florets triandrous ; pistil 0; terminal (or 

 central) one perfect, diandrous. Br. in Prodr. Fl. Nov. HolL 



*** Calyces many -flowered. 

 (Flowers all perfect, or upper florets only sometimes imperfect.} 



f Calyx of 1 valve. 

 28. LOLIUM. Cal. lateral, fixed. Cor. 2-valved, firmly en- 



* In all the Grass tribe I use the almost universally adopted term of Seed 

 for Fruit. This fruit is of that kind called a Caryopsis, which is when the 

 seed is intimately united with the pericarp so as to form apparently but one 

 piece with it. 



f " Genus distinctisainmm, plures species compleeteno, in frigidis hc- 

 misphaerici utrinque provenientes." Br. I.e. 



