1898] COMPARATIVE MORPHOLOGY OF PISTILS 303 
ference between this and Anemone Caroliniana is that the ovules 
are further developed, some of them in fact having embryo sacs 
with two or four nuclei. Guignard describes3 and figures these 
accessory ovules in Clematis cirrhosa with embryo sacs containing 
two and four nuclei, showing conclusively their ovular nature. 
Some species of Anemone, too, have these accessory ovules 
developed to this extent, showing that in this there is no dis- 
tinction between the two genera, 
DELPHINIUM CAROLINIANUM. Owing to the ease with which 
the material could be obtained, this species was the one chiefly 
used in the study of the multiovulate type of pistil. Caltha 
leptosepala was used to corroborate the results obtained from 
the study of this species. It was evident from figures and 
descriptions of the pistils of this type, published elsewhere, that 
these two species give us typical examples, and it was accord- 
ingly decided that it would be unnecessary to make careful 
study of other species. Unfortunately it was impossible to 
obtain specimens of those genera with biovulate pistils, forming 
perhaps the transition from the uniovulate to the multiovulate 
genera. The pistils arise at the top of the nearly hemispherical 
receptacle. The stamens develop acropetally. The pistils do 
not show any signs of appearing until all the stamens have begun 
to develop. Each pistil first appears as a small conical papilla 
with rounded apex, and increases in size very rapidly. As this 
increase in size progresses, the ventral side begins to be hol- 
lowed out, until by the time that the pistil is a millimeter in 
height, and a little narrower than high, it has become closed 
by the meeting of the laminae (figs. 27, 28). Soon the ovules 
begin to make their appearance as small papillae on the inturned 
edges of the carpellary leaf. These increase rapidly in number 
and size until the edges of the laminae of the pistil are occupied 
entirely by horizontally growing ovules (fig. 29). In Delphi- 
nium the. ovules arise opposite to each other, but later, owing to 
the crowding due to their growth in size, they become alter- 
3GUIGNARD, LEON: Récherches sur le sac embryonnaire des phanérogames 
angiospermes. Ann. Sci. Nat. Bot. VI. 13: 163. pi. 5. 1882. 
