I83-JED F33Y. 24. ]899. 



Circular No. 9.— (Agros. 39.) at » 



United States Department of Agrfcuitu?e? . 



DIVISION OF AGROSTOLOGY O > ' ' 



[Grass and Forage Plant Investigation.] ^• 



*• '^ ■' '•' A L 



, » . ... 



NEW SPECIES OF NORTH AMERICAN GRASSES. 



In the present circular are brought together the descriptions of a 

 number of new species of grasses, mostl}^ belonging to the genus 

 Poa, from the Avestern part of the United States. This form of issu- 

 ing descriptions is adopted to expedite publication and to allow the 

 citation of names in non-technical publications where new descrip- 

 tions can not well be given. 



1. POA CAPILLARIFOLIA Scribn. & Williams, sp. nov. 



A smooth, csespitose peremiial, 3-4.5 dm. high, with long, thread-like leaves, 

 marcescent basal sheaths and narrow greenish panicle, about 4 or 5 cm. long. 

 Culm with the short, basal internodes usiially much exceeded by the sheaths. 

 Leaves soft, 1-2 dm. in length, abxmdantly produced from numerous inti'a- 

 vaginal innovations. Sheaths smooth, striate, the basal ones swollen, mem- 

 branous, and persistent. Panicle narrowly ovate, or oblong in outline, 

 closely flowered, lower branches solitary or in twos, or more rarely in threes, 

 the lower ones from 1 l-'i cm. in length ; spikelets 8-4-flowered, 5-6 mm. long ; 

 empty glumes unecpial, scabrous on the back, 3-nerved, scarious-margined, 

 the lower one Ijroadly lanceolate, aciite, 2i mm. long, the upper obtuse, 

 3 mm. long, both often erose-dentate above ; flowering glumes thin, 5-nerved, 

 broadly ovate, obtixse or acutish, minutely hispid on the back above and on 

 the keel and nerves, with broad hyaline margins and usually erose-dentate 

 apex, about '^ mm. in length. The palet nearly or quite equaling the 

 flowering glume, hyaline, with distinct grt^enish cili ate -hispid keels and 

 erose-dentate apex. 



Type specimen No. 2614, Geo. Hansen, California. 



Allied to Poa cusickii Vasey, but with smaller flowers, longer and more filiform 

 leaves and smaller, closer panicle. In some ways this species is intermediate 

 between P. cu.siekii Vasey and P. idahoensls Beal. 



Poa vaseyochloa Scribn., new name. P. pulchella Vasey (1882), not Salisb. 

 nor Pari. 



PoA NUDATA Scribn., new name. Poa capillaris Scribn. (1898), not Linn. 



2. POA SAXATILIS Scribn. & Williams, sp. nov. 



A slender, closely csespitose perennial, 2^3^ dm., tall, with soft, smooth leaves 

 and stems and lax, variegated panicles fr<mi 5-7 cm. long. Culms erect or 

 somewhat geniculate below, very smooth, with conspicuous purplish nodes. 

 Leaves flat, rather obtusely pointed, those of the stem from 1^2 cm. or more 

 in length ; those of the sterile shoots aboi;t twice as long. Sheaths smooth, 

 or basal ones sparsely pubescent, striate, shorter than the internodes, the 

 lower ones swollen and often split open by the growth of the intravaginal 

 shoots. Ligule 2-3 mm. long, acute. Panicle branches ascending, filiform 

 and somewhat flexuous, usually in twos, the lower ones about 4 cm. long, 

 flower- bearing above the middle. Spikelets compressed, lanceolate, 3-5- 

 flowered, 6-9 mm. long. Empty glumes somewhat unequal, obtuse, or sub- 

 acute, 3-nerved, smooth, about 4 mm. long. Flowering ghmie obscurely 



