MORPHOLOGY OF THE FRUIT AND SEED 277 



Fig. 603. 



Fie. 604. 



extremity,, as in the Pansy or Heartsease {fig. 000), when it is 

 internal. 



The embryo is said to be axile or axial when it has the same 

 direction as the axis of the seed, as in Heartsease (fig. 600, ^jQ ; 

 or when this condition is not found, it is ahaxile or eccentric, 

 3.S in Bvmex {fig. 606, pT). In the latter case, the embryo is 

 frequently altogether on the outside of the albumen, and 

 directly below the integuments, as in Mirdbilis Jalapa {fig. 

 607, e) and Lychnis {fig. 608, emh), when it is described as 

 peripherical. 



We have already observed that the radicle as a general 

 character is turned towards the micropyle {fig. 606, ?•), and the 

 cotyledonary extremity is then directed to the ohalaza, ch. Some 

 apparent exceptions to these relative positions occur in the 

 EuphorbiaeesG and a few other 

 plants ; but such are merely acci- 

 dental deviations arising from cer- 

 tain irregularities in the course of 

 the development of the parts of the 

 seed. 



While the relation of the radicle 

 and cotyledonary portion is thus 

 seen to be generally constant, it 

 necessarily happens, from the vary- 

 ing relation which the hilum bears 

 to the micropyle and chalaza, 

 that its relation to the radicle and 

 cotyledonary portion of the embryo 

 must also vary in like manner. 

 Thus in an orthotropous seed, as 

 Bumex {fig. 606), the chalaza 

 and hilum coincide with each 

 other ; the radicle is turned towards 

 the apex of the seed, and the cotyledonary portion to the 

 ohalaza and hilum ; in this case the embryo is said to be anti- 

 tropous or inverted {figs. 476 and 606). In an anatropous 

 seed, as that of the Heartsease {fig. 600), where the micropyle 

 is contiguous to the hilum, h, and the chalaza, ch, at the 

 opposite extremity, the radicle, r, points towards the hilum or 

 base of the seed, and the embryo is said to be e7-ect or homo- 

 tropous. In a campylotropous seed, where the chalaza and 

 micropyle are both near to the hilum, as in Lychnis {fig. 608), 

 the two extremities of the embryo, which in such cases is 



Fill. 603. Embryo o( the Woad 

 {/satis Hnctoria). 1. Undivided. 

 2. Horizontal section, c. Cotyle- 

 dons, r. Radicle. Fig. 604. 



Embryoof the Wallflower {Cheir- 

 anthus CheiH). 1. Undivided. 

 2. Horizontalsection. r. Eadicle. 

 c. Cotyledons. 



