﻿Eustachvs in North America 447 



side of a triangular rachis and more or less divergent from it. 

 Scales 4, or very rarely 5, the fifth rudimentary, the awns, when 

 present, hispidulous ; outer 2 scales empty, membranous, keeled. 

 1 -nerved, the nerve hispidulous, the first scale acute or acutish, 

 shorter than the awned second, which is broad and oblong, 

 2-toothed or 2-lobed, or sometimes truncate, at the apex ; third 

 scale firmer, chartaceous and deep brown or almost black at ma- 

 turity, keeled, 3-nerved, the nerves pilose, awnless or bearing a 

 mere rudimentary awn, enclosing a perfect flower and a 2-nerved 

 palet as long as or a little shorter than the scale, the nerves cil- 

 iolate ; fourth scale similar in texture to the third, awnless or rarely 

 short -awned, rounded to truncate at the apex, which is inrolled on 

 the margins, 3-nerved, the nerves glabrous. Stamens 3. Styles 

 distinct ; stigmas plumose. Grain free, elliptic. 



Species about 10, confined to the tropics and the warmer parts 

 of the temperate zones in America. 



Key to tlie Species. 



Spikekts 2 mm. long ; third and fourth scales awnless, or the former with a mere 



dorsal point. 

 Spikes usually 4-6, rarely more ; second scale of the spikelet manifestly 2-toothed 



at the apex ; leaves usually 3-7 mm. wide. . \. E. petraea. 



Spikes 10-25 > second scale of the spikelet truncate at the apex ; leaves usually 



1 cm. or more wide. 2 - E ' &""?' 



Spikelets 3 mm. or more long; third and fourth scales awned. 



Spikes usually 1 or 2, rarely 3 ; third scale of the spikelet exceeding 3 mm. long. 



Spikes 4-6 ; third scale of the spikelet less than 3 mm. long. 



3. E. Eloridana. 



4. E. negieda. 



1- Eustachvs petraea (Sw.) Desv. Nuov. Bull. Soc. Philom. 



2 : 189. 1S10. 



Chloris petraea Sw. Prod. 25. 1788. 



Chloris Swartziana Doell, Mart. Fl. Bras. 2* : 68. 1883. 



Culms 3-1 1 dm. tall, much compressed, at length branched, 

 often decumbent or prostrate at the base and rooting at the lower 

 n °des ; nodes 2-5 : basal leaves crowded, culm leaves 2-4 at the 

 'over nodes ; sheaths much compressed, keeled, striate, those at 

 [he base and lower nodes equitant ; ligule a scarious ciholate ring 

 le ss than . 5 mm. wide ; blades 3 dm. or less long, usually under 

 2 dm., 10 mm. or less wide, commonly 6 mm. or under, smooth 

 on both surfaces, rough on the margins : inflorescence at length 

 much exserted, consisting of 3-1 1, usually 4-6, erect or slightly 

 spreading spikes, 4-1 1 cm. long : spikelets about 2 mm. long : 



