210 PITTONIA. 
The “anomalous character” on which D. Hendersoni is 
based is the operculate capsule; but that is far from being 
any peculiarity of that species. 
D. ellipticum, to which was attributed a capsule opening 
normally, and even some of the plants confounded with D. 
Jeffreyi in the Revision, have the same dehiscence which is 
supposed to be found only in D. Hendersoni; and all the 
forms of the genus which inhabit either the plains or lower 
mountains of California, have just that dehiscence. Only the 
true D. Jeffreyi, a plant of the high Sierra, has the valvular 
dehiscence of the typical species. 
But there are characters, of equal weight with any dis- 
covered by Dr. Gray’s Oregon correspondent, which appear 
to have remained unnoticed hitherto; although clear indica- 
tions of them will appear in even the herbarium specimens, 
when once they shall have been pointed out. I refer first to 
certain characteristics of the roots. The roots of all the 
species consist of a bundle of fleshy fibres, which are attached 
to a distinct crown from which arise, in their season, the leaves 
and scapes. The roots themselves are renewed annually; . 
only the crown remaining perennial. 
Now the species fall into two marked groups according to 
the season of the year at which the new roots are formed ; for 
in some they are produced at the beginning of the dry season, 
remaining dormant but alive until autumn ; in others they do 
not form until the beginning of the wet season. Moreover, 
in the species whose new roots are made at the end of spring, 
the old roots simply die while the new ones are being formed ; 
but in those whose roots are not renewed until autumn, the 
old roots, in spring-time, do not die, but are, in part at least, 
transformed into tubers destined to become new plants. 
In D. Hendersoni, for example, the roots, having performed 
their first function in the nourishing of the plant until the 
flowering, become detached from the crown, diminish in 
length, increase in thiekness, and ultimately become tubers 
each with a bud at the upper end. After the five months of 
summer drough', the parent erown sends out its new set of 
