MANUAL OF THE GRASSES OF THE UNITED STATES 187 



2. Cynosurus echinatus L. (Fig. 367, B.) Annual; culms 20 to 

 40 cm tall; blades short; panicle subcapitate, 1 to 4 cm long, bristly; 

 pairs of spikelets 7 to 10 mm long; lemmas with awns 5 to 10 mm 

 long. © — Open ground, British Columbia; Oregon to central 

 California; introduced from Europe. 



23. LAMARCKIA Moench 



(Achyrodes Boehmer) 



Spikelets of two kinds, in fascicles, the terminal one of each fascicle 

 fertile, the others sterile; fertile spikelet with 1 perfect floret on a 

 slender stipe and a rudimentary floret on a long rachilla-joint, both 

 awned, the glumes narrow, acuminate or short-awned, 1 -nerved; 

 lemma broader, scarcely nerved, bearing just below the apex a deli- 

 cate awn; sterile spikelets linear, 1 to 3 in each fascicle, consisting of 

 2 glumes similar to those of the fertile spikelet, and numerous im- 

 bricate, obtuse, awnless, empty lemmas, a reduced spikelet similar to 

 the fertile one borne on the pedicel with one of the sterile ones. — 

 Low annual with flat blades and oblong, 1-sided, dense panicles, 

 the crowded fascicles drooping, the fertile being hidden, except the 

 awns, by the numerous sterile ones; fascicles 

 falling entire. Type species, Lamarckia aurea. 

 Named for J. B. Lamarck. 



1. Lamarckia aurea (L.) Moench. Golden- 

 top. (Fig. 369.) Culms erect or decumbent 

 at base, 10 to 40 cm tall; blades soft, 3 to 7 mm 

 wide; panicle dense, 2 to 7 cm long, 1 to 2 cm 

 wide, shining, golden-yellow to purplish, the FlGV c*lll7™ltet£ onof 

 branches short, erect, the branchlets capillary, 



flexuous; pedicels fascicled, pubescent, with a tuft of long whitish hairs 

 at the base; fertile spikelet about 2 mm long, the awn of lemma about 

 twice as long as the spikelet; sterile spikelet 6 to 8 mm long, o 

 — Open ground and waste places, Texas, Arizona, southern California, 

 and northern Mexico; introduced from the Mediterranean region. 

 Sometimes cultivated for ornament. 



24. ARUNDO L. 



Spikelets several-flowered, the florets successively smaller, the 

 summits of all about equal, the rachilla glabrous, disarticulating above 

 the glumes and between the florets; glumes somewhat unequal, 

 membranaceous, 3-nerved, narrow, tapering into a slender point, 

 about as long as the spikelet; lemmas thin, 3-nerved, densely and 

 softly long-pilose, gradually narrowed at the summit, the nerves 

 ending in slender teeth, the middle one extending into a straight awn. 

 Tall perennial reeds, with broad linear blades and large plumelike 

 terminal panicles. Type species, Arundo donax. Arundo, the ancient 

 Latin name. 



1. Arundo donax L. Giant reed. (Fig. 370.). Culms stout, in 

 large clumps, 2 to 6 m tall, sparingly branching, from thick knotty 

 rhizomes; blades numerous, elongate, 5 to 7 cm wide on the main 

 culm, conspicuously distichous, spaced rather evenly along the culm, 

 the margin scabrous; panicle dense, erect, 30 to 60 cm long; spikelets 

 12 mm long. % — Along irrigation ditches, Texas to southern 



