220 
H. F. Wernham. 
florets of dense inflorescences. This type of zygomorphy, we shall 
see, is not accompanied by oligomery of the andrcecium. And 
3rd, the ovary is composed not infrequently of more than two 
carpels, although the general tendency is toward the bicarpellary 
gynoecium, as reflected in Composite. The bicarpellate pistil thus 
represents a tendency in progress in the Infers, whereas in 
Bicarpellatae this tendency was already realized in their hypothetical 
proximate common ancestor. The completeness of this realization 
presented us with one of our most formidable difficulties in the way 
of discovering the true ancestry of the Contort® (see chapter IV); 
and we shall find, on the other hand, that the probable ancestry 
of the Infer® is not so obscure. 
* * * * 
Rubiales. 
This cohort consisted, in former editions of Engler’s system, 
of the two families Rubiaceae and Caprifoliaceae (including Adoxa) 
only, and so coincided with Bentham and Hooker’s cohort of the 
same name. Valerianaceae and Dipsacaceae were associated to 
form the cohort Dipsacales (Aggregate); the latter is now merged 
into Rubiales, with such justification as will be suggested later in 
the present chapter. 
Rubincece. Of the five families concerned, Rubiaceae is by far 
the largest in point of number of species, containing nearly eight 
times the number included in the other families taken together. 
How far, however, they are to be regarded as composing a truly 
natural family is open to question, as will appear presently. For 
Rubiaceae display a very wide range of structure, both vegetative 
and reproductive ; the tribe Galieae, to which the British species 
are confined, is the least representative in the whole family. For 
the most part Rubiaceae comprise tropical trees and shrubs, 
herbaceous forms, apart from Galieae, being decidedly exceptional. 
The only essential character of the rubiaceous flower which is 
so far constant as to rank as critical is the presence of a regular, 
isostemonous, epigynous,—-and, of course, sympetalous—corolla ; 
and with this may be coupled the vegetative characters of opposite 
(occasionally whorled) leaves with entire margins and interpetiolar 
stipules (except in Galieae). The combination of these characters 
in any given plant is sufficient to proclaim it a Rubiacea beyond the 
possibility of question. 
The corolla displays in some rare cases a leaning toward 
zygomorphy, e.g., Capirona, Coutarea, Ferdinandusa, Dorothea. In 
