398 CHALAZA RAPHE. [BOOK i. 



of the ovule, a communication between the two is always 

 maintained by means of a vascular cord, called the raphe 

 (Plate V. fig. 24. e, 25./). This raphe, which originates in 

 the placenta, runs up one side of the ovule, until it reaches the 

 base of the nucleus : and there it expands into a vascular disk 

 or plate, which is called the chalaza (Plate V. fig. 24. /. 25. g). 

 As the chalaza is uniformly at the base of the nucleus, it will 

 follow that, in orthotropal and campylotropal ovules, it is 

 confounded with the hilum; while it is only distinguished 

 in anatropal ones, in which alone it is distinctly to be 

 recognised. 



In addition to these there is the amphitropal ovule, whose 

 foraminal and chalazal ends are transverse with respect to the 

 hilum, which is connected with the latter by a short raphe ; 

 and the semianatropal, which is only different from the last, 

 in the ovule being parallel with the funiculus instead of being 

 at right angles with it. 



The following figures give a comparative plan of these 

 ovules : 



a ode, 



a, Orthotropal, or atropal ; b, campylotropal ; c, anatropal ; d, amphitropal ; e, semiana- 

 tropal. In these figures * represents the chalaza, and " the foramen. 



When an ovule grows erect from the base of the ovary, it 

 is called erect ; when from a little above the base, ascending ; 

 when it hangs from the summit of the cavity, it is pendulous ; 

 and when from a little below the summit, it is suspended. 



It has been remarked that the raphe or vascular extension 

 of the placenta always occupies the side next the ventral 

 suture of the ovary ; and that when, as in Euonymus, it is 

 turned towards the dorsal suture, that circumstance arises 

 from an alteration in the position of the ovule subsequent to 

 its being fertilised. 



This curious fact has been capitally illustrated by Schleiden : 

 " Robert Brown," says this writer, " struck by finding in the 



