CHORIZAXTHE. 49 



drawing on the nourishing material previously stored up. Accordingly, 

 with the early winter rains we find the various species of Chorizanthe 

 promptly germinating, and soon spreading their clustered radical leaves 

 in the warm winter sunlight. There is thus accumulated in the thick- 

 ened axis of growth Tclosely resembling a reduced biennial) the neces- 

 sary stores for future use. As showing, in a remarkable manner, the 

 sensitiveness of mature germs in this genus to the stimulus of moisture, 

 it not unfrequently happened that in subjecting specimens to soaking 

 for subsequent dissection, when left over night in tepid water, on the 

 following morning radicles were found protruding half an inch or more. 

 As the dry, warm season advances, the radical leaves, having performed 

 their functions, gradually wither and disappear, and the flowering stems, 

 usually copiously branched, shoot up, commencing at once in the lowest 

 axils the development of flower and fniit, to be continued upward in a 

 dichotomous centrifugal inflorescence as long as the season of growth 

 allows, or the stores of nourishment hold out. It thus happens that 

 according to the season or location a vigorous or depauperate growth 

 is produced, but never, even in the most reduced specimens, is there 

 an entire failure of flower and fruit. This explains most satisfactorily 

 why this class of plants is naturally confined to a limited geographical 

 range, as well as their more obvious morphological peculiarities. WTiat 

 are the special conditions which in corresponding South American dis- 

 tricts determine a prevalence of perennial suftruticose species in this 

 genus, though an interesting question, lies outside of the line of present 

 investigation. 



The special contrivances for dissemination, so frequently noticed in 

 this genus in the sharply-hooked awns attached to the seed containing 

 involucres, and the commonly fragile joints at maturity, is one of the 

 important factors that materially assists in the maintenance and exten- 

 sion of such species, thus enabling them to avail themselves of any 

 accidental means of transportation. 



In the succeeding synopsis and rearrangement of species, in accord 

 ance with the preceding views, in order to give completeness to the 

 subject, I have added detailed descriptions of each species in a uniform 

 order, so that the resemblance and contrast of each can be most read- 

 ily seen, whether in the field or the study. For fuller details and syn- 

 onyms, reference may be had to the authorities herein referred to. 



[Pro.-. D. a. N. S., Vol. IV.] T [April :a, 18&1.] 



