296 
H. F. Wernham. 
typically cordate at the base ; and the scorpioid inflorescence of 
the Boraginaceae, their surface hispid with coarse hairs. In the 
gynaecium these two orders display considerable advance, the 
ovules numbering constantly two per carpel. The Boraginaceae 
shew still further specialization in the fruit character; the four 
one-seeded nutlets, whorled about a gynophore derived from the 
base of the gynobasic style, constitute a familiar feature. The 
flowers of this order, moreover, are highly specialized, in many 
cases, in relation to insect-visits, as witness the hairs or scales 
closing the corolla-mouth in several forms, the anther-cone in 
Bor ago, and so forth. 
These two natural orders, then, must be regarded as relatively 
advanced, the Boraginaceae considerably more so than the Convol- 
vulaceae. But there is very little indication in either of the 
fundamental tendency expressed in the large majority of the 
Tubiflorae, namely, zygomorphy of the flower coupled with oligomery 
of the andrcecium; such as there is will be referred to shortly. 
The same lack of such indication is observable in the other two 
natural orders of Engler’s transitional group, Polemoniaceae and 
Hydrophyllaceae. These are relatively small orders, occurring 
chiefly in the new world ; the first consists of about 200, the second 
of about 170 species. In both, the flower is regular and the stamens 
equal in number to the corolla-lobes. The members of both are 
advanced in so far that they have adopted the herbaceous habit in 
nearly all cases; but in regard to the tendency to ovule-reduction, 
referred to above, they are far less advanced than the Boraginaceae, 
for the number of ovules is variable, although a tendency to reduction 
is traceable. The scorpioid inflorescence of Boraginacese is a 
common feature also in Hydrophyllaceae, and may be regarded as a 
type of floral aggregation in relation to insect-visits comparable 
with the verticillasters and capitate inflorescences found so commonly 
in Labiatae. The Hydrophyllaceae are, moreover, exceptional in 
another direction ; the ovary is typically unilocular. 
The Polemoniaceae are curious in regard to the carpel-number, 
which is invariably three ; this constitutes the sole exception of any 
material extent to the constancy of the bicarpellary condition 
among Tubiflorae, and, indeed, among the so-called Bicarpellatae as 
a whole (supra, p. 218). We shall refer to this point again when 
we approach the question of the origin and affinities of the group. 
It is to the Solanaceae that we must look for strong indications 
of that zygomorphy which is the essential character of the cohort 
