218 THYTOTOMY. 



341. 



The {X)sition of tlie stigma, as well with respect to the 

 male parts as to the pistillum in particular, presents remark- 

 able differences. We know that in the Orchideae, a com- 

 mon coliimna genitalium supports both the stigma and the 

 two antherae. The same union takes place in the Stylidea% 

 in Cleone, in Podostevwn, and in Andrachne, as well as in 

 Aristolochia. In some of the Proteaceae and Scitamineaf, 

 the two sorts of sexual organs become united at their base, 

 and thus furnish a proof of the kindred nature of their struc- 

 ture. 



A remarkable difference of arrangement takes place in the 

 stigmata of the Syngenesious plants. The proper surface of 

 the stigmata appears to be less intended for the collecting of 

 the pollen, than what are called by Cassini the Collectors, or 

 hairy surfaces which are placed opposite to the proper stig- 

 mata. In many of the Caryophylleae, the greater part of 

 the pistillum is of the same consistence with the stigma, whilst 

 in the Saxifrages and Oxalidae, as also in the Ericoe, only 

 the extreme point of the pistil can be called the Stigma. 



CHAP. II. 



PHYTOCHEMY, Oil DOCTllINE OF THE COMPOSI- 

 TION OF PLANTS. 



Sennebier, Physiologie vegetale, torn. ii. p. 298. 



Keith, Physiological Botany, vol. i. p. 375, vol. ii. 



K. Sprengel, Von der Natur und dem Buu der Geuachse. 



J. Ingenhousz, Versuche uber die Ernahrung der Pflantzcn. 



Treviranus, Biologic. B. 4. 



A. V. Humboldt, Aphorismen aus der Chemischcn-Physiologie der PHantzen. 



Einhof in Hermbstadt's Archiv fur Agricultur-Chemic. 



H. Davy, Elements of Agricultural Chemistry. 



J. F. John, Ucber die Ernahrung der Pflantzen. 



