OUTGROWTHS. 209 



alternate with the petals forms the effective androecium. For 

 the scale-like body before each petal, and even slightly adnate 

 to its base (in P. Caroliniana about 3-parted, as in Fig. 400, but 

 in P. palustris a thin scale, fringed with more numerous gland- 

 tipped filaments), is plainly outside the stamens in tho full-grown 

 flower-bud. But Eichler and Drude have found 

 that it is inside in the early bud. 1 Wherefore, if 

 these stamen-like bodies really represent a circle 

 of the andrceciura, it must be the inner one ; and 

 that is the more probable view. 



382. Multiplication by chorisis in the g}TiO3cium 

 is not common ; but there are well marked in- 

 stances of it in all degrees. In Drosera, the 

 styles and stigmas are doubled (Fig. 402) ; in 

 Malvaceae, the same thing takes place in Pavonia 

 and its allies ; while in Malope and two other 

 genera of the same order the few normal carpels are multiplied, 

 evidently by chorisis, into an indefinite number of wholly distinct 



8. OUTGROWTHS. 



383. Proper chorisis is the congenital multiplication of one 

 organ into two or more of the same nature and office ; or at 

 least into two or more organs, even if dissimilar, as in the 

 American Lindens, in which one member of the cluster is a kind 

 of petal. Between this and the production by an organ of ap- 

 pendages, or outgrowths of little or no morphological signifi- 

 cation, there are many gradations ; as also between these and 

 mere cellular outgrowths from the surface, even down to 

 bristles and hairs. The latter, in all their variety and modifica- 

 tions, are properly outgrowths of the epidermis only, and there- 

 fore consist of extended cells, single or combined, unaccompanied 

 by vascular or woody tissue. To them has been given the 

 general name of Trichomes (Trichoma, pi. trichomata), that. is 

 structures of which hairs are the t}-pe. They may occur upon 

 the surface of any organ whatever. Their morphology is the 

 morphology of cells rather than of organs. They will therefore 

 be most conveniently illustrated under Vegetable Anatomy as 



1 Eichler in Fl. Brasil., Sauvagesiacae, & Bliithend. ii. 424 ; Drude in Lin- 

 naea, xxxix. 239. Eichler refers to this as a confirmation of Celakowsky's 

 explanation of obdiplostemony by posterior displacement. (3G5.) 



FIG. 402. Pistil of Drosera filiformis with tricarpellary ovary (transversely divided), 

 and six styles, i. e. three, and each two-parted. 



