FOURTH GROUP.- -SEED-PLANTS. 



branch at their margins in the same manner and form anthers on the branches, the 

 stamens remain free below ; but in other points the conditions are the same l . 



The stamens not unfrequently suffer remarkable displacements caused by the 

 intercalary growth of the tissue of the torus at the place of their insertion, and these 

 displacements are also commonly treated as cases of coalescence of parts. Thus 

 the stamens frequently unite with the calyx or with the corolla ; in this case in the 

 mature state the filaments seem to grow from the inner surface of the perianth-leaves ; 

 but the early stages of development show that the perianth-leaves and the stamens 

 emerge one after the other and separately from the torus ; it is not till afterwards that 

 intercalary growth begins at the spot in the torus at which they both appeared, and 

 thus a lamella grows up which is in structure the basal portion of the perianth-leaf, and 

 at the same time bears the stamen, which thus appears to grow from the middle of the 



FIG. 282. Flower ofJIfatngZeffa glabrata, one of the 

 Proteaceae. A before the opening of the flower. B the 

 flower unfolded. C the gynaeceum ; gp the gynophore. D 

 transverse section of the ovary. fruit ripening on its 

 stalk. 



FiG. 283. A flower of Sterculia Ba- 

 langhas ; gs the gynophore, f ovary, n 

 stigma. B transverse section of the ovary. 



inner face of the perianth-leaf. In Fig. 282 J3, p is a perianth-leaf, a an anther 

 which is sessile upon it ; these stood at first separately one above the other on the 

 young torus, and the portion of the leaf underneath a and p was formed some time 

 after by intercalary growth, and carried up with it the true perianth-leaf p and the 

 stamen a together. This mode of coalescence is especially frequent in flowers in 

 which the parts of the corolla are united laterally into a tube, as in the Compositae, 

 Labiatae, Valerianeae and other families. But the stamens may also unite in various 

 ways with the gynaeceum. In Sterculia Balanghas (Fig. 283 A) the connection is 

 only apparent and simply arises from the fact, that the small sessile stamens imme- 

 diately beneath the ovary are carried up with it by the elongation of a part of the 

 torus, and appear from their small size to be mere appendages of the large ovary ; 

 the part that bears the two organs, the gonophore, is here therefore an internode of 



double rows on the cohering margins (placentas) ; that which takes place here inside in regard to 

 the ovules takes place in the other case outside in the formation of the filaments ; at the same time 

 a fresh comparative investigation of the history of development in the flower of the Malvaceae is 

 desirable. 



1 See Payer, /. c., on page 346. 



