Rubiales. 
223 
Hoff mania, Antirrhcea, Palicourea) ; and altogether the proportion 
of species with gynaecium of more than two carpels represents 
about 10% of the whole family. The gynaecium is thus usually 
bicarpellary, but the tendency to this condition is clearly traceable 
through a series of polycarpellary forms. In regard to the segmen¬ 
tation of the ovary, the unilocular condition is quite exceptional, 
occurring in less than 4% of the family ( Gardenia, Coussarea, 
Faramea, Opercularia , etc.). In most of these cases the placentation 
is parietal, there being thus no evidence of the derivation of this 
unilocularity from the degradation of ancestral septa. There is, 
on the contrary, evidence of septation by the meeting of projecting 
parietal placentae, e.g., Gardenia, Posoqueria, Oxyanthus, and others. 
The number of loculi, then, is usually equal to the carpel-number; 
there is no indication of “ secondary ” septation (schizocarpy), so 
that there are usually two chambers in the rubiaceous ovary. In 
the small minority with unilocular ovary this latter condition not 
impossibly represents the relic in the family of a primitively 
unseptate ovary, and so cannot be regarded as a progressive step 
in the direction of the higher Inferse (e.g., Dipsacaceae) with unilocular 
ovary. The suggested retention rather than the acquisition in 
descent of the unilocular state is parallelled in Tubiflorae, as we 
have seen in chapter VI. 
The number of ovules in the ovary is, perhaps, the most 
important feature concerned in Rubiaceae, especially in view of its 
employment as a criterion of the primary two-fold division of the 
family. Its critical value has, however, been called into question, 
for it involves in some cases the wide separation of forms which 
differ generically in no other particular save that of the number of 
ovules borne in each loculus of the ovary. This is illustrated in 
the comparison, e.g., of Webeva with Pavetta or Ixova, of Tricalysia 
with Coffea, aiUrophyllum with Lasianthus, of the tribe Oldenlandieae 
with the tribe Spermacoceae, and so on. The tribe Naucleae, again 
—apparently a very natural group—includes both multiovulate and 
uniovulate forms. 
It must be admitted, on the other hand, that broadly speaking 
the members of the multiovulate series (Cinchonoideae) differ 
materially in general facies from those of the uniovulate series 
(Coffeoideae). Bentham and Hooker recognized a third series, 
characterized by the presence of two ovules in each chamber of the 
ovary. This section included barely fifteen species, comprised in 
the two tribes Cruckshanksieae and Retiniphylleae; but the component 
