THE FLOWER (. SUPPRESSION, ETC . ) 71 
carpels of male flowers (above), &c. Suppression of a whole 
whorl has probably occurred in the evolution of many flowers 
with only one whorl of stamens, in the petals of apetalous 
flowers, eg. many Caryophyllaceae, in the perianth of such 
naked flowers as Achlys, and so on. 
Change of Form of the Receptacle is a frequent 
case. In primitive flowers, and in many now existing, the 
axis is more or less elongated, with the carpels at the top 
or superior , and the other organs arranged below them or 
hypogynous (A in fig. 5). In Fragaria, Potentilla, &c. the 
receptacle in its development becomes flattened on the top 
by the more rapid growth of the sides, so that in section it 
has a kind of v shape. In Acer, Ruta, and many other 
plants of the orders placed in Disciflorae by Bentham and 
Hooker (see Chap. II.) the flattening is above the calyx, 
so that a disc is formed in the base of the flower, bearing 
corolla, stamens and carpels. In Rosaceae, Crassulaceae, 
&c. (most of the Calyciflorae of Bentham and Hooker), 
however, the calyx also is borne on the edge of the flattened 
receptacle. Usually the growth of the sides goes on so far 
as to make the upper surface concave, so that a shallow or 
deep cup is formed, with the calyx springing from its margin 
(B in fig. 5). The texture of the cup is usually similar to 
that of the calyx, often to such an extent that it is impossible 
to point out by mere inspection of the outside where one 
ends and the other begins, and we may if we please regard 
the phenomenon as one of concrescence of the calyx, with 
the corolla and stamens also taking part. This is partially 
the older view expressed in the term “ Calyciflorae.” The 
corolla usually springs from the margin of the cup, and the 
stamens lower down in it. In these flowers, while the carpels 
or gynoeceum are still superior, the other organs, springing 
around them, are termed perigynous, even if the tube of the 
flower be so deep that they spring above the carpels. 
Epigyny is another line along which evolution seems to 
have proceeded. The genus Saxifraga may perhaps serve 
as an illustration. In it there are some species with almost 
hypogynous flowers ; others have a more cup-like receptacle, 
but the carpels are united at the sides to the cup. Some 
show this phenomenon to a very slight extent, others to 
such a degree that only the styles remain free, the ovary 
