natural Family of Plants called Composites. 97 
cannot appear very paradoxical to consider them as both of the 
same nature. 
In Dipsaceae, however, there is no instance of the outer calyx 
containing more than one flow'er, and the evidence afforded by 
inflorescence on this subject is not altogether satisfactory. 
In Dipsacus it has been long noticed that expansion begins 
about the middle of the spike, and proceeds in opposite direc¬ 
tions from the point of commencement: this order is evidently 
more analogous to that of the compound than of the simple spike; 
there being several instances of spikes manifestly compound, 
where the same inversion of the upper part exists. 
But a fact, which I do not find any where observed, respecting 
the inflorescence of certain species of Scabiosa, particularly sue - 
cisa and atropurpurea , is not so easily reconcilable with the com¬ 
pound spike: in these, and I have reason to think in many other 
species of the genus, the expansion begins simultaneously at the 
base and middle of the capitulum, proceeding regularly upwards 
from both points. Were this the case in all Scabiosae, the com¬ 
pound nature of the spike in Dipsaceae, although by no means 
proved, might be considered not improbable : there are, how r ever, 
several species of the genus in which the order of expansion is 
altogether that of the simple spike. 
Connected with the subject of inflorescence, I may remark that 
priority of development, whether among similar parts in the same 
flower or the different flowers of the same spike, is generally accom¬ 
panied with greater perfection of these parts or flowers, and ap¬ 
parently with greater power of resisting the ordinary causes of 
abortion or obliteration. 
1 have formerly * observed respecting several natural families of 
plants, in which the stamina are in a determinate number, but a 
* In Prodr. Flor. Nov. Hoil. vol. i. and Appendix to Flinders’s Voyage to Terra Australis.. 
v or,, xir. o number 
