U6 BOTANICAL GAZETTE. 



spirals. The laws (13, 14) that g-oveni the common system apply 

 equally to any other. The mode of finding the cycle from the secon- 

 dary spirals (15, 16) is also the same as in the common system. 



28. The phyllotaxis of the leaves is generally uniformin the same 

 species. Thus in the Oak the leaves are always alternate; in the 

 Maple, they are always opposite ; and in Galiuin always whorled. The 

 cycle of the cone of Hemlock Spruce is always 5-13. The direction 

 of the sjiirals does not appear to be uniform in the same species, but, 

 in some individuals the sf)iral winds to the right, and in others it 

 winds to the left. In the same individual plant, the spiral usually 

 pursues the same direction upon the branches as uj)on the stem. 



Flowers and SNOW.^This season of the year calls to mind some 

 ^observations concerning flowers and snow in Colorado. 



Among the first flowers of spring, those that must live and bloom 

 through many snow storms, are Toivnsendia sericea, Sisymbrium canes- 

 cens, Cymopterus glomeratus and montanus, Viola NuUallii, Leucocri- 

 num, Corydalis, Thlaspi, &c. Last year the Toumsendia was in blos- 

 som as early as Feb. 14th, and Pldox ca)iescens<, with many other flow- 

 ers, by the middle of March. A number of plants are in bloom in 

 April and covered every year by the spring snows. In May I have 

 seen Crataegus coccifiea white with flowers made still whiter by the 

 damp snow, with Astragalus and Vicia and very many other plants in 

 full bloom buried beneath a foot of snow. • 



The spring snows do not seem to injure the plants or flowers in the 

 least and many of them are benefited by the increase of moisture. 



A snow storm in June is said to have covered all the dry parks with 

 sunflowers, H. ■petiolaris and lenticularis. The alpine plants growing 

 where there is a frost nearly every night in the year, must be well 

 able to stand the cold. In July I once saw a Trollius laxus in blos- 

 som, growing out from a hole about one foot in diameter, in the cen- 

 ter of a large snow drift. As the snow drifts disappear the plants 

 rapidly grow and blossom. Some of the drifts melt away much soon- 

 er than others, and plants growing there are much in advance of those 

 inhabiting the place of late melting snows. On Mt. Ouray, above 

 timber line, there is a slope which, in August, is beautifully covered 

 with the large golden flowered Ranuncidus adoneus. On one portion 

 from which the snow early melted, the plants are almost out of flow- 

 er ; at another part they are in their greatest perfection, and in other 

 parts they are in their youth, closel}^ following up the retreating 

 snow drift. 



