THEORY OF THE STRUCTURE OF PLANTS. 337 
smaller stamens and lateral sepals, bear the seeds on their edges and 
unite a stigmatic segment from each to form the stigmas immediately 
over their line of junction; the other pair of carpels lies just within 
this, and is almost uniformly abortive, the remains forming the parti- 
tion, but in Parolinia, as we have seen, it produces stigmas. 
It is remarkable that whilst analogies for the illustration of the 
structure of Brassicaceae have been sought—not always judiciously— 
from Papaveraceae and Fumariaceae, so little use has been made of 
Capparidaceae the order really most nearly related to Brassicaceae, and 
belonging to the same alliance. In this we have the same tendency 
te circles of four parts, but slight irregularity intrudes to a greater 
extent, and the number of stamens is increased by the development in 
many instances of those which in Brassicaceae only appear as glands 
im a rudimentary condition, and of more numerous circles. The 
tarpels are generally supported on a protrusion of the axis, so that the 
fruit seems elevated on a stalk within the flower, a circumstance not 
uuknown in Brassicaceae, as is seen in the remarkable genus Stanleya. 
The irregular number of stamens, 6 instead of 8 or 12, is found in many 
Capparidaceae. In some of them a spurious partition more or less 
perfect occurs, and has probably the same origin as in Brassicaceae, in 
others the carpels are reduced to two, and the pod is like one of a 
eruciform flower without the partition. In others again more carpels 
than two seem to be developed, perhaps a whole circle of four. 
1 must now explain the theory of Moquin Tandon and Webb, 
adopted and defended by Dr. Gray, for explaining the peculiarity of 
the Androecium in Brassicaceae. They leave the glands out of con- 
sideration and reduce the six stamens to a single circle of four 
primitive parts, by regarding each pair of the longer stamens as one 
original organ, separated into two by a principle called chorisis or 
deduplication. This principle, first proposed for the explanation of 
certain phenomena by Duval, consists in a supposed tendency of parts 
originally single, and which must be taken as one in explanation of 
symmetry, to divide themselves either into several layers, one in front 
of the other, or in several portions standing side by side. This has 
been extensively applied by some botanical theorists, but Dr. Lindley 
entirely rejects it, maintaining that there is no sufficient evidence of 
any single case. I cannot but admit that it affords some very 
plausible explanations of difficult cases, yet some of those most relied 
upon, seem to' me very doubtful; several obviously to admit of other 
Von. V. 2A 
