26 BOTANICAL INFORMATION. 



111, Helianthus 34, Chrysocoma 63, Galium septentrionale, Ery- 

 simum asperum, Purshia tridentata, Pentstemon pusillum, and 

 238, Gymnandra 230; sometimes with a poplar grove occurs on 

 the sloping side, of P. betuUsfolia, and a dense carpety under- 

 growth of Myginda myrtifolia. There is no trace of saline 

 soil on these table-lands, not even at the bottom of the chasm 

 in the plain above mentioned ; it is the more remarkable that 

 I found several saline plants on the former, as Atripkx 

 argentea and the above Stanleya. Sida dissecta deserves to 

 be noticed as one of the handsomest of the genus, far more 

 brilliant in colour than Sida coccinea. The others are com- 

 mon plants, already mentioned or occurring in other localities. 



M. simplex and vivipara, which remain firm above the hard gravelly sur- 

 face, or granite rock. There is, however, a great difference in the seasons, 

 which is in favour of the latter two, while the former are yet covered with 

 deep snow ; these are already vegetating (May), and about the middle of 

 June the pulpy fruit is already coloured, on the growth of the same 

 spring ; so that the plant has the whole long summer to harden its 

 texture for the very severe winter. Those in the higher altitudes are 

 scarcely in bloom (beginning of September), when snow-storms have 

 already set in, therefore the fruit has not time to ripen the same year, and 

 the fructification is, so to say, biennial, or on the growth of last year. 



Among the Opunties is the fragilis, Nutt. the lowest and not seldom 

 covered with sand, but it also occurs on firm soils, though a prostrate spe- 

 cies ; the same is the case with O. vulgaris on the granite rocks in the 

 neighbourhood of New York, and in the Sandy Oak-barrens of Northern 

 Illinois, near Beards-Town ; O. Missurica remains erect and quite firm. 



The MammUlariee afford quite a seasonable refreshment in the Missouri 

 Plains ; though only during the time of growth while the fibres are tender. 

 In taste they resemble raw cucumbers ; the same may be said of the young 

 shoots of the Opuntim ; the latter, however, proved a great annoyance to the 

 travellers, especially as there are no other shoes worn in that part of 

 the wilderness than of buck-skin ; they are more easily avoided by day, 

 but it is quite impossible to move about at night, even horses get lamed 

 by stepping carelessly in these thorny bushes. In the month of June 

 they show their large bronze-yellow flowers in abundance, which are only 

 open during noon-day hours ; and in warm weather the stamens evince 

 the same irritability as those of Berberis and Sparmannia. On the upper- 

 most waters of the Colorado, in a great desert, I found a species of Coccus 

 inhabiting this Cactus copiously, the insect was in every respect like the 

 C. Cacti, but large. 



