OVULES. 281 



In the anatropous, the inequalit}- of growth is mainly confined 

 to the base or chalazal region, which ends by becoming upper- 

 most ; and the full-grown ovule has the ap- 

 pearance of being inverted on and adherent 

 to the upper portion of its funiculus, the 

 rhaphe. Fig. 589-597 illustrate the course d 

 of development from a comparatively early 

 period. 



529. The direction of anatropy or of other 

 turning of the ovule in the course of growth 

 is somewhat diverse. But in general, when- 

 ever ovules are in pairs, the two turn from 

 each other, in the manner of Fig. 315, and so present their 

 rhaphes back to back. The rhaphe-bearing may therefore be 

 called the dorsal side of the anatropous ovule. The same is true 

 in the case of numerous ovules, viz., those of one half of the 

 placenta (or one leaf-margin) turn their backs to those of the 

 other. When such ovules are solitary or in single rows, and 

 either ascending or hanging, the rhaphe is usually on the side 

 next to the placenta or ventral suture, as in Fig. 579 : it is then 

 said to be ventral (i. e., next the ventral suture), or adverse to 

 the placenta. In certain cases, mostly in hanging ovules, as in 

 Fig. 581, the rhaphe looks in the opposite direction, toward the 

 dorsal suture or midrib of a simple ovary : it is then said to be 

 dorsal or averse from the placenta. 1 



1 By comparison of Fig. 578 with 576 and the like, it may be perceived 

 that the difference is explicable by a kind of resupination of the ovule of 

 the former. That of Ranunculus, if inserted higher, would become hori- 

 zontal ; and if the insertion were transferred to the very summit of the cell, 

 it would be suspended and the rhaphe averse, as in Fig. 581. Upon this 

 conception, Euphorbia and its allies has normally suspended ovules, the 

 rhaphe being next the placental axis, and Buxus and its allies, resupinately 

 suspended ovules, the rhaphe averse. The propriety of regarding the ad- 

 verse rhaphe as the normal condition is confirmed by the fact that the only 

 instance we know of solitary erect ovules from the base of the cell having 

 the rhaphe averse is that of Rhamnus and its allies ; and here it was shown 

 by Bennett (in PI. Javan. Rar. 131), and confirmed by the analyses of 

 Sprague (Gray, Gen. 111. ii. 168, plates 163-169), that the rhaphe of the young 

 ovules is ventral, so that the dorsal position, when it occurs, is the result 

 of torsion. J. G. Agardh (in his Theor. Syst. PI. 178, &c.) maintains the 

 contrary, but is not sustained by later observers. 



Accordingly, even if we adopted Agardh's estimate of the botanical 

 value of the characters here considered, we should prefer to express these 

 differences in the phraseology above indicated, and not to adopt his terms, 



FIG. 597. Same as 595 more magnified ; the outer coat, (a), the inner (6), nucleus (c), 

 and the bundle of spiral ducts (d) in the rhaphe (running from placenta to chalaza) 

 indicated. 



