MAGNOLIACEJE. 



133 



ceous, the inner one membranous. This last is immediately sur- 

 rounding the fieshy albumen, which contains a small dicoty- 



Magnolia purpurea. 

 Fig. 170. 

 Longitudinal section of seed. 



Magnolia Yulan. 

 Fig. 171. 

 Flower without its periiiiitli. 



ledonous embryo towards its apex (%. 170). In the flower of 

 Magnolia Yulan, of which it has been proposed to make a special 

 genus under the name of Yidania,^ the lower portion of the recep- 

 tacle forms a dome-shaped swelling (ligs. 1G7, l.-l), into the base 

 of which is inserted the perianth. This, instead of consisting of six 

 petaloid leaves, and three others, green like those of an ordinary 

 calyx, usually presents nine leaves in three whorls, all similar. 



the raphe and its branches. As these vessels 

 contain little but gas when mature, we have 

 found a means of disclosing the path of the vas- 

 cular network, by leaving the seed for some time 

 in tincture of iodine. All the cells then become 

 violet, and almost black, while the tracheae remain 

 only of a clear brown tint. We can now follow 

 and dissect out all the tracheal network in the 

 thickness of the parenchyma, nmch as we isolate 

 the injected vessels of an animal. The bundle in 

 the raphe, while giving forth branches on either 

 side, proceeds to the chalaza, where it bends up 

 to enter the interior of the seed. We must here 

 describe a peculiar orifice in the testaceous middle 

 coat, diametrically oi)posite the micropyle, and 

 never encroached \\\wn by the incrustations of Llio 

 deep coat, 'i'he physiological importance of this 

 new organ will be realized — a canal, of dcifinite out- 

 line, which can be traversed by a very fine mct;illic 

 style without any destruction of tissue, and which 



we call the ' heleropyle.' The testaceous coat, 

 which retains its primitive orthotropy, is thus 

 furnislied with two ])olar apertures. As to the 

 superficial fieshy enveloj)e, tlie older botanists 

 termed it an aril, an appellation which recent 

 authors have not ado])ted; and yet it forms a 

 sort of generalized aril, far more worthy of the 

 name than those partial hypertrojihies of the 

 outer seed coat to which it is now-a-days usnallv 

 applied." 



' SrAcn, Suit, a Buffon, vii. 102. In this geiuis 

 the author includes three species : 1'^ Y. cuii- 

 spicua (Magnolia conspicua Salisb. — M. Yulan 

 Desf.); 2° Y. japonica, (M. ohovata Thg. ; — 

 M. demulata Lamk. ; — M. discolor Vkxt. ; — 

 M. purpurea Cintr.) ; of this M. Soulaugiana 

 Sweet and Uliijlora Lamk., are considered 

 simply forms; 3° Y. Cohux (.]/. tonientoxa 

 Tug.; — M. gracilis Salisd. ; — ,)/. Kolmi 

 DC). 



