Rubiales. 
227 
florae; and the importance of this consideration will become 
manifest when we premise that it is to an umbellifloral ancestry 
that we shall find reason to refer the rubialian stock {infra). 
Caprifoliaceae are especially interesting in this regard, as they 
exhibit the tendency to form a rayed inflorescence comparable with 
that in Umbelliferae and Composite. Thus in our British Viburnum 
Opulus the outer flowers of the dense flat-topped cymes are large, 
oblique, and sterile, the whole inflorescence tending to become the 
biological equivalent of a single flower. 
The ovary in Caprifoliaceae, in contrast with Rubiaceae, consists 
of more than two carpels in as many as 75% of the total number of 
species; the most usual number is three,—a common number for 
polycarpellary ovaries generally (see chapter II). The number of 
loculi is usually equal to that of the carpels ; but a feature of special 
interest is the frequently-occurring phenomenon of degradation of 
all save one of the loculi when the ovary comes to maturity. This 
is well illustrated in Viburnum, and a transitional state occurs in 
the tribe Linnaeeae ; in Linncea there are two effete ovules in each 
of two of the three ovary-chambers, and one only in the third, the 
latter alone maturing as a seed. A condition similar in kind is found 
in Symphoricarpus and Dipelta, the other two genera of the tribe; 
and this tribe, comprising twenty species or more, may be regarded 
as representing the mean between those forms with many ovules in 
each ovary cell ( Lonicera , Diervilla, etc.), and those with only one 
( Viburnum , Sambucus, etc.) In Lonicera the number of ovules is 
usually few, sometimes two only; so that, as in Rubiaceae, there is 
a continuous series of forms illustrating the progression from the 
multiovulate to the uniovulate condition. About half the species in 
the family are characterized by the latter, and the Linnaeeae 
represent together less than 10%. 
The fruit displays no marked specialization; it is usually a 
berry or drupe, rarely a capsule ( Diervilla ). 
* * * 
The two families which we have just considered are clearly 
linked in close affinity, and in view of the wide range of their 
essential characters, coupled with their prevailingly woody habit, 
we have been led to conclude that they represent a relatively 
primitive stock, the Rubialian Stock. Into the origin of that stock 
we must presently enquire; but it will be convenient first to examine 
its immediate progeny, the herbaceous. 
