252 NATURAL HISTORY OF PLANTS. 



7. The transformation of certain stamens into sterile petaloid blades,' 

 — This transformation is not of generic value, for there is no genus 

 in which all the species present it. In Jbcremoa, in U/wna, it occurs 

 in a single species ; as well as in a few American species of Xi/lojjia. 

 It takes place, as we have seen, sometimes with the outer stamens, 

 sometimes, but far more rarely, with the inner ones." But in this 

 order it does not seem to be due to cultivation. 



S. The conformation of the upper part of the receptacle. — We 

 may distinguish the form of complete concavity, with epigyuous 

 insertion of all the floral appendages exterior to the pistil, from that 

 in which the concavity is restricted to the summit of the receptacle, 

 or to a region not involving the insertion of the perianth, which in 

 this case is always hypogynous and inserted below the androceum. 

 Accordingly, while complete concavity has sufficed to mark out one 

 particular series, the Eupomatlcte, the partial deformity may vary 

 from species to species in one and the same genus. The deep sac 

 on whose outer surface the stamens are inserted in most species 

 of Xylopia may become a slight pit, or even a plane surface in 

 some.* The same diversity is found in Artabofrp," Ihwalohi/s, &c., 

 though in these genera the cavity is never so marked as in certain 

 Xi/lojjias. 



9. The ascending or descending direction of the ovules. — It will 

 be seen that this has no more importance here than in any other 

 group, when we have to deal with numerous ovules arranged along the 

 whole length of the ventral angle of the ovary. In the same species, 

 in the same ovary, here as elsewhere we find ovules nearly horizontal 

 at the centre of the placenta, while they are more or less oblique, 

 ascending or descending, as they approach the top or bottom of the 

 cell. But when the ovules are solitary or few in nuiubiT wo do not 



' See Ailtinsoniii, viii. 32G. (p. 21i>) ; mid -V. malai/iuKi lIooK. K. i TnoMS., 



^ Tliirt ])ec-uliurity Iiuh been obRervcil in (lie in tliis respect atVurds n transit iun between tlivso 



gcnuH Anusti<iorea alone (p. 207). anil the other species of Xyloput, its receptacle 



^ Prof. Oi.iVKU, in his enuwierMtion of the being like an elongafed cone solid for alM)ut 



Anonmiti hi ihis Flont of Tiojiiidl Afrir(i{\.'M), two-thirds of its hcij;ht, with the upper thinl 



an nn|)ubli>lK'd work, of w hiih he Inis kindW fa- alone hollowed into a shallow pit to receive the 



voured nie with the ]proof sheets [this work insertion of the carjH'ls. 



was |)ublislitil ill iKCiNj, hiis had no hesitation ' Ksjiecially in the sjiecies of the sit'tion /'urar- 



in referring Mtludumm ajricimutn lJi;NTn., to (ttbutiyv, sucli as J', hixaffytut MlQ. The snr- 



Xylopia, despite it4i convex receptacle. This face on which the cnrjK-ls are in«erte<l is Hut, 



has nearly the wune form in most species of but it rises in a circle all round, projecting to a 



J/iifjziliti, which we have included in \i/lnj)i<, fnir height in proportion. 



