GRASS FAMILY. 73 



nodes so that at maturity the internodes fall away with the attached 

 spikelet; when the rachis is not jointed the rachilla is jointed above 

 the bracts. Spikelets (in ours) in 2 opposite rows, solitary or 2 or 

 more side by side at each node, sessile or very rarely pedicellate, all 

 perfect or polygamous or when there are three at a node the central 

 perfect or polygamous the two lateral sometimes imperfect, 1 to 

 many-flowered, when many-flowered the uppermost flowers imperfect. 



A. Spikeleis sessile. 

 Spikelets solitary at the nodes of the rachis. 

 Flowers 1 or 2 in a spikelet; spike slender, the spikelets deeply sunk in 

 notches of the rachis. — Subtribe Lepture.e. 



Bractlet awnless; callus naked , 40. Leptcbus. 



Bractlet awned; callus hairy .41. Sceibneeia. 



Flowers 3 or more in a spikelet.— Subtribe Tbiticem. 

 Spikelets placed edgewise to the rachis, so that the backs of one row of 

 braetlets are turned toward the notch; bract 1 only, except In the 



terminal spikelet 42. LOLTDM. 



Spikelets placed ilatwise to the rachis so that one side of each row of bract- 

 lets is turned towards the notch; bracts 2 to each spikelet 



43. Ageopyeon. 

 Spikelets 2 or more side by side at the nodes of Ihe rachis.— Subtribe Elyme;e. 



Flowers 2 or more in each spikelet; rachis jointed at the nodes or not. 

 Bracts but little smaller than the braetlets .... . . 44. Elymus. 



Bracts minute, or obsolete and leaving only scars 4-5. Aspeeella. 



Flowers solitary in each spikelet; rachis jointeji at the nodes, each Internode 

 at maturity falling awa.v with the attached spikelet . . .46. Hoedeum. 

 B, Spikelets, at least the lateral ones, pedicellate. 

 Flowers 2 or more in each spikelet; rachis jointed at the nodes or not 



44, Elymus. 

 Flowers solitary in each spikelet; rachis jointed at the nodes, each internode 



at maturity falling away with the attached spikelet . . 46. Horedtjm. 



40. LEPTURUS R. Br. Hard-gsass. 

 Ours slender, branching annuals. Inflorescence a simple, terminal, 

 slender, cylindrical, jointed spike, at maturity each internode sepa^ 

 rating with the attached spikelet. Spikelets sessile, distichous, alter- 

 nate, solitary in the notches of the axis, their backs turned towards 

 the notches; uppermost spikelet terminal. Bracts 1 or 2, exceeding 

 the bractlet, approximate in the lower, opposite in the upper spikelet, 

 sub-equal, hard and rigid, narrow, 5-nerved, acute, awnless, one 

 spreading when in flower. Flowers 2, or 1 with an empty bractlet 

 above it. Braetlets sub-equal, hyaline, acute (in ours), awnless. 

 Palea 2-nerved. Scales entire, glabrous. Stamens 3 or fewer. 

 (Greek leptos, slender, oura, tail, referring to the slender, tail-like 

 spikes.) 



1. L. cylindricus Trin. Cylindrical Hard-grass. Stems 12 

 to 14 in. high; spike 3 to 6 in. long, stout, cylindrical, straight; 

 lateral spikelets with only 1 bract; braetlets acute. 



Native of the Mediterranean Region; introduced along the coast 

 near San Francisco: Tiburon, 1886, Greene; Petaluma Marshes, 1896, 

 Leckenby; San Pablo and Pinole Caiions, in adobe soil, abundant, 

 1900, Davy. June-July. 



2. L. incurvatus (L.) Trin. Curved Hakd-gkass. Usually has 

 a more slender, incurved spike, with the lateral spikelets subtended 

 hy 2 bracts. 



