155 



there are some peculiar and interesting forms wliich are deserving of 

 notice. The collection is quite full, also, ia several difficult genera, and 

 serves to increase and make more satisfactory our information respect- 

 ing them. 



One of the rarities of the collection is a ver^- diminutive species of 

 Vilfa, which may be characterized as follows : 



Yilfa minima. Culms erect, branched at the base : spikes very slen- 

 der, erect, terminal, and lateral ; lateral ones partly included in the 

 sheaths; llowers alternate, few, half a line long, pointed; glumes mem- 

 branaceous, obtuse, about half as long as the llowers ; palets nearly equal 

 in length ; stamens, three ; leaves mostly radical, short, strongly nerved, 

 lower sheaths inflated. This grass is from one to one and a half inches 

 high, slender and delicate, and was found growing on wet shores 

 around Twin Lakes, Colorado. 



Sporoholns asperifoUus, N. and M., occnrs in a very luxuriant form, 

 many of the specimens having 2-3 flowered spikelets. Many of these 

 have the grain affected with a black smut, {Tllletia caries, Tul.) This 

 seems to be an abundant grass in some localities. The genus Calama- 

 grostis is represented in the collection by o species, viz, C. LangsdorffH^ 

 Trin.; G.sylratica, D.C.; C.stricta, Trin.; C. Lajjponica, Triu.; and C. confi- 

 nis, Nutt. The last-mentioned species gro^ws tall, and is cut for hay. 

 The seed, however, is subject to an ergot, which diflers, says Mr. C. H. 

 Peck, from Cladiceps purpurea in its smaller size and in its color. 



A few specimens of the delicate Stipa MongoUca, Turcz., were collected. 

 It appears to be very rare. Catabrosa aqnatica, Bean., was collected in 

 wet bogs near Gray's Peak. 



Xo genus of grasses gives more trouble to the botanist than Poa, 

 Much confusion and uncertainty has prevailed as to the species of this 

 genus in the Rocky Mountains. The specimens in the collection are 

 very numerous, and embrace at least twelve well-marked forms or spe- 

 cies, most of which are pretty well known in collections, some, ho"wever,^ 

 under provisional names, and some others which probably have not yet 

 been properly defined. 



The following are some of the species as commonly received : Foa arc- 

 tica, 11. Br.; Poa alpina, L.; Poa pratensis, L.; Poa ca'sia, Sm.; Poa sero- 

 tina, Ehr.; Poa sylresfris, Gr.; Poa flexuosa, Muhl.; Poa tenui/oUa, Nutt.; 

 Poa Andina, Xntt. In addition to these is a species which approaches 

 P. hrevi/olia, Mnhl., but differs in some important particulars. The 

 leaves are rather rigid, involute and cuspidate pointed. The cau- 

 line ones are very short, radical ones, 4-6 inches long. The culms are 1 to 

 1 J feet high, from running root-stocks. The branches of the panicle are 

 mostly in pairs, slender, rather close and erect, flowering above the 

 middle; the spikelets 3 to 4 flowered, flowers not webbed at the base. 



A species described by Mr. Watson, in King's Keport, under the 

 doubtful name of Poa nipina, occurs in considerable quantity in the col- 

 lection, and with considerable variety of form. It differs so materially 

 from the Linnrean species that it should have a distinct name. It seems 

 to have a wide range, at elevations of 0,000-10,000 feet, and might 

 very appropriately be called Port mojitana,. 



The genus Festuca is represented by the following species: F.tenella, 

 Willd.; F. ovina, L,; in several varieties; F. microsfqchys, Xutt.; F. hrevi/o- 

 lia, Br.; and F. scabrelJa, Hook., and by another, numbered 406 in the. 

 collection, whose specific position is yet undetermined. It may be char- 

 acterized as follows: 



Festuca, No. 406. Spikelets cylindrical, lanceolate, acute, 3-5 flowered, 

 5-G lines long; glumes membranaceous, shorter than the flowers, nearly 



