18 Gramineae 



dehiscent by lateral slits. Pistillate flowers with num- 

 erous distinct 1-ovuled ovaries and small persistent 

 stigmas. Achenes densely aggregated in globose heads, 

 compressed ; seeds curved ; embryo horseshoe-shaped. 



1. S. latifolia Willd. Roots tock slender ; scapes 0. 2-1 m. high, 

 angled ; leaves very variable, ovate-sagittate to linear, acute, 

 lobes more or less divergent, acuminate; flowers monoecious 

 with the lower verticils pistillate or dioecious, 2-4 mm. wide; 

 petals white; stamens numerous 25-35; filaments glabrous; 

 pistillate pedicels shorter than the staminate; achenes broadly 

 winged on both margins, 3 mm. long, with a lateral horizontal or 

 curving beak, /^-/3 its length. (S. variabilis Engelm.) 



Occasional on margins of ponds about Los Angeles. 



Family 6. GRAMINEAE. GRASS FAMILY. 



Annual or perennial herbs of various habit, rarely 

 shrubs or trees. Stems (culms) generally hollow or 

 sometimes solid, the nodes closed. Leaves sheathing, 

 the sheaths usually split to the base on the side opposite 

 the blade, a scarious or cartilaginous ring (ligule) 

 borne at the base of the leaf-blade. Inflorescence spicate, 

 racemose or paniculate, consisting of spikelets composed 

 of 2-many 2-ranked imbricated bracts (glumes), 

 the 2 lowest in the complete spikelet always empty, 

 1 or both sometimes wanting. One or more of the 

 upper glumes usually contains in the axil a flower, which 

 is usually inclosed by a bract-like awnless organ called 

 the palea, placed opposite the glume with its back to the 

 axis (rachilla) of the spikelet, generally 2-keeled. 

 Flowers perfect or staminate, sometimes monoecious or 

 dioecious, subtended by 1-3, usually 2 minute hyaline 

 scales (lodicules). placed at the base of the ovary oppo- 

 site the palea. Stamens 1-6, usually 3 ; anthers 2-celled 

 versatile longitudinally dehiscent. Ovary 1-celled, 1- 

 ovuled ; styles 1-3, usually 2 and lateral ; stigmas 



