324 



NATURAL HISTORY OF PLANTS. 



Saxifraga crassifolia. 



a slightly dilated receptacle, bearing a calyx of five sepals, quincunc- 

 ial in the bud, and a corolla of five free equal petals, imbricated in 

 the bud. The stamens, also perigynous and free, like the petals, are 

 ten in number, five superposed to the sepals, five, smaller, to the 

 petals. Each consists of a filament bearing a two-celled anther of 

 introrse or submarginal longitudinal dehiscence. 1 The gynseceum 

 is free, mostly superior ; it consists of two 2 carpels, antero- posterior, 



free or united below. Each has 

 a one-celled ovary, covered at 

 the base with a thin layer of 

 glandular tissue representing a 

 rudimentary disk, and tapering 

 above into a style whose dilated 

 apex is covered with stigmatic 

 papilla?. In the ventral angle 

 of the ovary is a parietal pla- 

 centa, bearing an indefinite 

 number of anatropous ovules. 

 The fruit is dry, formed of two independent follicles, which open 

 lengthwise to set free the indefinite small elongated seeds. These 

 contain within their coats a fleshy albumen in whose axis is an 

 •embryo of very variable length. 



In other species, such as S. rotundifolia, Ilircidus, &c, the gynseceum 

 is still quite free ; and not only are the stamens hypogynous or sub- 

 perigynous, but there is also an annular glandular disk, pretty high 

 between their insertion and the base of the ovary. This consists of 

 two carpels, united by the ventral surface so as to form two complete 

 cells, with the placentas on the septum. We find numerous transi- 

 tional forms between the two types of gynseceal organization ; and in 

 S. Cymbalaria, umbrosa, hederacea, &c, for instance, the free ovary is 

 two-celled below, dividing above into two quite distinct horns, 

 wherein the corresponding part of the placenta becomes quite free. 

 In other species again, with a gynseceum of variable form, the 



Fig. 359. 



Long. sect, of flower. 



Fig. 360. 

 Diagram. 



1 The pollen consists of elongated grains, with 

 three folds. In water they become spherical with 

 three bands. The bands are covered with papillae 

 in S. crassifolia, but lack thein in S. Cotyledon. 

 (H. Mohl, in Ann. Sc. Nat., ser. 2, iii. 331.) 



2 The normal number is exceptionally three or 



four, tapering above into as many cupitate styles 

 in S. trigyna R£m. (in Ann. Sc. Nat., ser. 3, viii. 

 235), a little csespitose species growing about the 

 snow-line in Bolivia ; but yet its other floral 

 verticils are pentamerous. 





