PROF. OLIVER ON A NEW GENUS OF BEGONIACE X. 363 
hitherto the most marked. Between Hillebrandia and Datiscaceæ we find the following 
characters in common,—unisexual flowers, adherent ovary open above, with parietal 
multiovulate placentas, carpels opposed to sepals or perianth-segments, and a seed and 
embryo closely similar—most of them characters, with the exception of the open ovary 
now first described, already indicated by Dr. Lindley. 
The seed and embryo in Hillebrandia and Datisca (the latter the only genus of Datis- 
caceæ of which I have examined well-developed seeds) are almost identical, agreeing in 
the areolate testa, and in the relative proportions of the cotyledons and radicle of the 
exalbuminous embryo. 
As occasionally happens when new plants turn up illustrating affinities in this way, 
we have found, mingled in Hillebrandia with these characters so strongly inclining 
towards Datiscaceæ, another character (that of the existence of true petals) apparently 
pointing in a different direction. This character does not, however, appear to warrant 
any new or decided opinion in respect of the affinities of Begoniaceæ, neither weakening 
nor particularly strengthening the views which have hitherto met with most favour. It 
must be borne in mind that in the female flower of Datisca, according to M. Payer*, the 
three inner perianth-segments (which alternate with the three outer, forming a sex-partite 
perianth, in the male) are arrested at a very early stage of development, .... “à peine 
nées s'atrophient et l’on n’en aperçoit bientôt plus aucune trace.” 
DESCRIPTION OF THE PLATE. 
PLATE XLVI. 
Fig. 1. Male flower, laid open so as to show the petals. 
2. Single stamen of the same. 
3. Female flower, with pair of bracts. 
4. The same laid open, showing the petals and minute capitate glands (which can hardly be 
regarded as staminodia?) scattered along the line of insertion of the calyx-lobes. 
9. Transverse section of ovary. 
6 & 7. Style, back and front. 
8. Single petal, and one of the perigynous glands (?), of the female flower. 
9. Mature capsule. 
* Organ. Végétale, p. 372, t. 31, quoted also by À. DeCandolle, Prod. xv. 410. 
