214 TRANS. OF THE ACAD. OF SCIENCE. 



the seed, dropping it at maturity ; cotyledons, as in most spe- 

 cies, (i, rarely 5; in P. excelsa I find 8, or rarely 9, (not 2-3, 

 as Endlicher inadvertently stated,) and in the alpine speci- 

 mens, mentioned above, only 6 cotyledons. 



Picea Menziesii, the only other species of Colorado, is en- 

 tirely subalpine, occurring between the limits of 7,000 and 

 9,000 feet, in low, moist or marshy soil, especially on the bor- 

 ders of streams; it is, as Dr. Parry informs me, a tree of a 

 more oval outline, pointed upwards, with a more rapidly ta- 

 pering trunk; thicker (\ in.), grayish, moderately rough bark; 

 rapidly-growing (annual rings H--2 1 on an average), harsh- 

 grained, brittle, knotty, resinous wood ; stout, light colored, 

 smooth, glossy branehlets ; stout, broad, sharply-pointed 

 leaves; longer (9—121.) male and female aments, the latter 

 composed of pale, glistening, orbicular scales, which are many 

 times longer than the minute bract; cylindric cones, 3-4^ 

 inches long, drooping perpendicularly with the branch or 

 usually at an angle with it, abundant even on young (12-15 

 feet high) trees, crowded especially towards the top of the 

 tree and very conspicuous, whitish at maturity but turning 

 light brown and persisting on the tree for another year until 

 the new crop matures; scales elongated rhombic, 9—11 1. long, 

 truncate, more than twice as long as the seed with its triangu- 

 lar obovate wing. The alpine P. Williamsonii, Newb., from 

 the Cascade Mountains, Oregon, which I have not been able 

 to compare, seems to be well distinguished by its peculiarly 

 reflexed scales. 



JVeic Species o^Gentiana, from the Alpine Regions of the 

 Rocky Mountains. By George Engelmann, M.D. 



Gentiana (Amarella) acuta, Michx. var. nana: pusilla, 

 subsimplex; calycis 4—5 fidi lobis insequalibus tubum corollsB 

 cceruleo-virescentis aequantibus; laeiniis corolhe fauce ciliis 

 paucis ornatse ovatis obtusis. 



On alpine slopes, together with G. prostrata in mats of 

 Silene aeaulis ; Parry, No. 309. — Stems H~2 inches high, 

 flowers 4-5 1. long; distinguished from the ordinary form by 

 the short and broad lobes of the corolla, which bear a i'ew 

 (1-4) single cili» at their base, and by the short oval anthers. 



G. acuta is evidently but a form, a geographical variety of 

 G. Amarella, as Dr. Hooker has indicated, and which is con- 

 firmed by our dwarf variety and other forms collected in Colo- 

 rado by '.Messrs. Hall & Harbour (No. 473) ; the characters of 

 acutish lobes of the corolla and small seeds do not hold good; 

 Dr. Parry's No. 307 has seeds as large as G. Amarella from 

 Prussia, and several forms have quite obtuse lobes. I have 



