288 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
of the grasses, never over 4m. high and sometimes so small that it 
has to be taken up on the blade of a penknife. 
Trisetum rosed, here described as new, holds the distinction of grow- 
ing at a higher altitude than any other flowering plant on the North 
American continent except Lestuca linida. In fact I found it at 13,500 
feet, the exact altitude at which 7° //x/da had been reported from 
Mount Orizaba, where Linden speaks of it as the ‘last phenogamous 
plant.” Festuca Iénida was also found on Popocatepetl, my highest 
point being 13,600 feet. These two species were found together at 
about 13,400 feet, and it is doubtless a mere question of chance which 
of them is found at the highest point. Both grow in and under the 
melting snow, pushing up along the tongues of exposed sand soon to be 
buried under a fresh fall of snow. 
The following critical notes and descriptions were furnished by Mr. 
Merrill: 
Stipa mucronata H.B. K. Nov. Gen. & Sp. Pl. 1: 125. 1815. 
Collected at an altitude of 3,390 meters, August 7 and 8, 1901 (no. 6035). 
Muhlenbergia quadridentata (H. Bb. K.) Trin. Uniflor. 194. 1824. 
Podosaemum quadridentatum H. B. K. Nov, Gen, & Sp. Pl. 1: 180. pl. 682. 1815. 
Collected at an altitude of 8,000 meters, August 22, 1901 (no. 6261). 
Sporobolus wolfii Vasey, Bull. Torr. Bot. Club. 10: 52. 1883. 
Vilfa mimima Vasey in Monthly Rept. U. §. Dept. Agr. March 155, 1874; U. 8. 
Geog. Surv. W. 100th Merid. 6: 282. pl. 27. f. 7-9. 1878, non Trin. 
Collected at an altitude of 3,600 meters, August 7 and 8, 1901 (no. 6014). 
This is a very remarkable species, not only in its minute size but 
also in its distribution. The only locality previously known is Twin 
Lakes, Colorado, where it was collected on sandy shores (no. L077, 
John Wolf, 1873). There is also a specimen in the United States 
National Herbarium from the same locality collected by C. W. Derry 
in Is75, The specimen from Popocatepetl matches Vasey’s type even 
to the most minute characters, and we do not hesitate in pronouncing 
them to be identical. That this species should be found in only two 
stations and so far apart as Twin Lakes, Colorado, and Mount Popo- 
catepetl, Mexico, is certainly remarkable, although it is very probable 
that it occurs at intermediate points,“ but has been overlooked by col- 
lectors, owing to its diminutive size. It has been suggested that 
Sporobolus wolfi is only a depauperate form of S. 77/form/s (Thurh.) 
Vasey, but the great disparity in size between the two and the much 
smaller spikelets of the former lead us to beheve that it is a valid 
species. 
Cinna poaeformis (II. B. kK.) Scribn. & Merrill, U.S. Dept. Agr. Div. Agros. 
Bull. 24:51. 1901. 
Deyeuria poaeforimes HW. Bo WK. Noy. Gen. & Sp. Pl 1: 146. 1815. 
“Collected in 1903 by J. N. Rose and Jos. H. Painter on Nevada de Toluca (no. 
6453) and at Cima, State of Mexico (no. 8062). 
