LK.SSON 18.] OVrLES. 123 



instance of it : it is shown in its place in the ovary in Fipr. 208, 

 also detached in Fig. 270, and a much more magnilied diagram of it 

 in Fig. 274. In this kind, the orilice (/) is at the top, the chalaza 

 and the hilum (r) are hlended at the hase or point of attachment, 

 which is at the opposite end ; and the axis of the ovule is straight. 



If such an ovule were to gj'ow on one side more than on the other, 

 and donlile up, or have its top pushed round as it enlarges, it would 

 become a 



(AiDipi/lofropoiis ov cunrd ovu\c, as in Cress and Chickweed (Fig. 

 271). Here the base remains as in the stiaight kind, but its apex 

 uith the orifice is brought round close to it. — Much the most com- 

 mon form of all is the 



Auatropous or inverted ovule. This is shown in Fig. 2G7, and 

 273 ; also a much eidarged section lengthwise, or diagram, in Fig. 

 27."). To understand it, we have only to suppose the first sort (Fig. 

 270) to be inverted on its stalk, or rather to have it.-J stalk bent 

 round, applied to one side of the ovule lengthwise, and to grow fast 

 to the coat down to near the orifice ( /") ; the hilum, therefore, where 

 the seed-stalk is to break away {/i), is close to tin; orilice; but the 

 chalaza (c) is here at the top of the ovule ; between it and the hilum 

 runs a ridge or cord, called the RJxtphe (r), which is simply that part 

 of the stalk which, Jis the ovule grew and turned over, adhered to its 

 surface. — L:i-stly, the 



Aiuphitropons or half-anatropons ovule (Fig. 272) difTcrs from 

 the last only in having a shorter rliaphe, ending about half-way 

 between the chalaza and the orifice. So the hilmn or attachment is 

 not far from the middle of one side, while the chalaza is at one end 

 and the orifice at the other. 



n2r.. The internal structure of the ovide is snnicirnlly displayrd 

 in the subjoined diagrams, representing a longitudinal >lice of two 



no. 07n. Onholmi)oii« oviiIp of niirkwlipat : r, hilum and rli.-il.nr.n : /, nrifiro. 



nc. 2TI. CamiiyloiroiMms oviiIp nf n Cliirkwerd : r, liihiin anil clinlnza ; /, oridrp. 



T\r, 07-^ Aii.|.liilrn|K>iis ovnlp of Mnllnw : /. oririrc ; A, liiliini ; r, rliaplte ; c, rlinlaia. 



FlU. 273. AnalniiKMis ovnlo of a Viulvt; llio parts Ivticrcd as in tlio last. 



