34 GRAMINEAB. 



1. L. californicus J. ('•. Smith. Type locality, Stockton, J. A. Sanford. 



GRAMINEAE. Grass Family. 

 By J. Burtt Davy. 



Ours annual or perennial herbs. Nodes solid, sometimes branching, the 

 lower often emitting secondary roots; internodes usually hollow at maturity 

 (pithy in most Andropogoneae, some Paniceae, etc.) the lowest sometimes 

 shortened and eorm-like. Leaves alternate, mostly sessile, the lower portion 

 (sheath) clasping the stem like a tube. Sheath lined by a membrane which 

 is usually prolonged beyond the point of union of sheath with blade as an 

 erect, usually hyaline projection (the ligule), sometimes reduced to a ring of 

 hairs or rarely obsolete. Blades narrow, mostly linear; veins parallel, some- 

 times in aquatic species united by cross veinlets. Flowers collected into diminu- 

 tive, spiciform, 1 to many-flowered clusters called spikelets, which are usually 

 subtended by a pair (rarely one or both obsolete) of membranous, charta- 

 ceous, coriaeceous or cartilaginous bracts. Spikelets arranged in spikes, racemes 

 or panicles. Flowers perfect, monoecious, polygamous, or rarely dioecious; 

 when monoecious the staminate and pistillate flowers may be in the same spike- 

 let (sometimes in Arrhenatherum), in separate spikelets, or in separate inflores- 

 cences as in Maize (Zea) ; when polygamous, the staminate flowers may be 

 either in the same spikelet, as in Holcus, etc., or more rarely in separate 

 spikelets as in many of the Andropogoneae. Flowers distichously arranged 

 on the axis (the rachilla) of the spikelet, each subtended by a pair of modi- 

 fied leaves (rarely 1 being obsolete) ; the lower of these (the bractlet) often 

 similar in texture to the bracts of the spikelet; the upper (the palea) 

 usually thinner, hyaline, with usually 2 nerves, mostly 2-keeled, the inflexed 

 margins enwrapping the flower. Within and at the base of the bractlet are 2 

 (rarely 1, 3 or more), usually minute organs (the scales) ; the scales at the 

 time of anthesis become turgid, pushing the bractlets and palea apart, thereby 

 allowing the anthers and stigmas to protrude; after anthesis they lose their 

 turgescence, becoming hyaline, and allow the bractlet and palea to close 

 again. Perianth obsolete, unless represented by the scales. Stamens usually 

 3, rarely 1, 2, 6 or more, hypogynous; filaments capillary; anthers 2-celled, 

 mostly versatile and pendulous at maturity, usually proterandrous. Ovary 

 superior, 1-celled, 1-ovuled. Styles usually 2, free, or more or less united below, 

 or obsolete; stigmas 2, widely branched and usually plumose, covering a large 

 area and thus specially arranged to catch pollen carried by the wind, usually 

 spirally branched, rarely barbellate with papillate cells. Fruit in ours an 

 achene, often adnate to the palea and sometimes also to the bractlet. Seed 

 in oui's adnate to the pericarp. Embryo small, outside the base of the 

 endosperm. 



KEY TO THE TRIBES 



A. Spikelets I -flowered, the flower perfect; or with 1 perfect (lower and 1 (rarely 2) 

 empty bractlets or staminate flowers below (rarely above) it. Dioecious species and 

 species with 2 or more perfecl (lowers should be looked for under B. 

 Hath bractlet and palea cartilaginous, coriaceous or chartaceous (at least distinctly firmer 



in texture than the bracts) and becoming indurated in fruit. 



Rachilla jointed below the- bracts so thai the spikelets fall from the pedicel entire; 

 spikelets terete, or flattened on the back only, not at all laterally compressed; either 

 strictly I -flowered or the perfect (lower subtended by 1 (never more) empty bractlet 

 or staminate flower; lower brad often herbaceous and usually much the smaller 



2. Paniceae, p. 36. 



Rachilla jointed above the bracts so that these remain after the flowers fall away; 

 spikelets laterally compressed on both sides; subtended by _' (.rarely only 1) some- 



