in the Stock (Matthiola incana). 481 
nevertheless reappear fairly constantly in the offspring under unchanged 
conditions. 
24. The widespread occurrence of reversionary fruit types indicates 
that the typical 4-carpelled siliqua and silicula have been derived by reduc¬ 
tion and consolidation from an earlier ground-plan, in which G = 4 (hollow) 
+ 4 (solid); which in turn arose by simple reduction from one composed of 
a much larger number of both kinds of carpels, this construction being yet 
again the result of consolidation from an all-valve type with G numerous. 
25 . This tetramerous constitution of the gynoecium lends considerable 
support to the view put forward by several earlier observers, that the 
Cruciferous flower is composed of strictly alternating whorls, and that the 
ground-plan is K4 C4A4 + 4 G4 + 4. The same causes which have led 
to the consolidation of the two carpels in the median plane have had their 
effect also on the members of the androecium which also lie in this plane, 
with the result that the posterior and anterior stamen have completely dis¬ 
appeared. To this same cause may also probably be attributed such 
inequality in the size of the two pairs of sepals as is not directly accounted 
for by the asymmetric distribution of the nectaries ; while the forces tending 
to reduction, which in the first instance caused G oc to become G4 + 4 (and 
perhaps A oc to become A 4 + 4), have led at a later stage to the complete 
suppression of the last members in the whole series —the second whorl of 
carpels. 
Concerning the Capp arid ace ae. 
26. The same processes of reduction and consolidation are exhibited 
here, as in the preceding families, the many-carpelled condition with both 
valve and solid carpels being exhibited by such forms as Cappans spmosa, L., 
the final 4-carpelled stage by the section Cleomidiae. 
Concerning the Resedaceae. 
27. Number of carpels three to eight. Where the carpels are separate, 
as in Asterocarpus (6), or with single-line sutures, as in Reseda luteola , L. (3), 
they are all of typical valve form with the stigma centred over the midrib. 
In R. luteola each edge is bordered by a placenta, hence the appearance of 
bifurcation as the two separate towards the top where the ovary is open. 
Where the valve junctions show a double outline the carpels are dimorphic, 
the extent of cohesion depending upon the height to which the solid carpels 
extend. As it is the latter which in this case bear the placentae, no 
bifurcation takes place. The stigmatic function is generally performed by 
the valve carpels, but in R. odorata , L., the solid carpels function as well or 
sometimes (according to Buchenau) alone. Reduction and consolidation 
combined reach their limit in Randonia with G 4. 
