10 



POACEAE. 



Stigmas borne below the apex of the 

 ovary. 

 2. Spikelets in 2-rowed secund spikes. (Chlorideae.) 

 Spikelets wholly deciduous. 



At least the empty scales of the spikelets persistent. 

 Spikelets with only one perfect flower. 

 No scales above the flowering one. 

 One or two empty scales above the flowering 

 one. 

 Spikelets with 2 or 3 perfect flowers. 



Spikes whorled, or close together ; spikelets im- 

 bricated. 

 Spikes distant ; spikelets alternate. 

 Spikelets in 2-rowed spikes, in depressions of the rachis. 



(HORDEAE.) 



Spikelets solitary at the nodes of the rachis. 

 Spikelets 2-6 at each node of the rachis. 



Spikelets 1-flowered. 



Spikelets 2-several-flowered. 



24. Bromus. 



25. Spartina. 



26. Capriola. 



27. Eustachys. 



28. Eleusine. 



29. Leptochloa. 



30. Lolium. 



31. Hordeum. 



32. Elymus. 



1. ANDROPOGON L. 



Perennial grasses witli usually long narrow leaves, and terminal and 

 axillary racemes. Spikelets in pairs at eacli node of the jointed hairy rachis, 

 one sessile and perfect, the other with a pedicel and either staminate, empty or 

 reduced to a single scale. Perfect spikelet consisting of 4 scales, the outer 2 

 coriaceous, the second keeled and acute, the two inner hyaline, the fourth more 

 or less awned and subtending a palet and perfect flower. Stamens 1-3. 

 Grain free. [Greek, in allusion to the bearded rachis.] About 150 species, 

 widely distributed in tropical and temperate regions. Type species: Andro- 

 pogon hirtum L. 



1. Andropogon virginicus L. 

 Virginia Beard-grass. (Fig. 6.) 

 Culms tufted, l5°-3° tall, many times 

 longer than the basal leaves ; sheaths, 

 at least the lower ones, more or less 

 tuberculate-hirsute on the margins; 

 leaves 16' long or less, more or less 

 hirsute on the upper surface near 

 the base; spathes l'-2' long, broad; 

 racemes generally in pairs about 1' 

 long; sessile spikelets li"-2" long, 

 the awn 5"-8" long; pedicellate 

 spikelet wanting or rarely present as 

 a minute scale. 



Paget Marsh, abundant in 1905 

 and 1913. Native. Eastern United 

 States. Flowers in late summer and 

 autumn. The light, hairy inflorescence 

 may readily have been transported by 

 hurricane winds. 



Andropogon Schoenanthus L., Lemon Grass, a grass with fragrant leaves, 

 is cultivated, and is reported as at times spontaneous after cultivation; it is 

 native of Old World tropics. 



2. HOLCUS L. 



Tall grasses, with usually broad flat leaf -blades and large terminal panicles, 

 their primary branches verticillate. Spikelets of 4 scales, in pairs, or in 3's 



