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 Lepturea:. 



Bractlet awnless; callus naked 40. Lepturus. 



Bractlet awned; callus hairy 41. Scribneria. 



Flowers 3 or more in a spikelet — Subtribe TRiTiCEiE. 

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

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

 terminal spikelet 42. Lolium. 



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

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



43. Agropyron. 



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

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



Bracts but little smaller than the bractlets 44. Elymus. 



Bracts minute, or obsolete and leaving only scars 45. Asperella. 



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

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

 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. Horedvm. 



40. LEPTURUS R. Br. Hard-grass. 

 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. Bractlets 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; bractlets acute. 



Native of the Mediterranean Region; introduced along the coast 

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

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

 1900, Davy. June-July. 



2. L. incurvatus (L.) Trin. Curved Hard-grass. Usually has 

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

 by 2 bracts. 



