374 Holm. — On Obolaria virginica . 
observed the same not only in the axils of the calyx-leaves, 
but also in those of the bracts and stem-leaves. 
In Obolaria the stamens are equal in length. The anthers 
were figured by Gray as sagittate, but they are not strictly so ; 
and the pollen-grains, which he described as ‘ globose and very 
smooth,’ are oblong, with the exine distinctly granulate. The 
ovary is one- celled, and contains a large number of ovules, 
which are scattered all over the interior surface of the two 
carpels. In this respect it differs from the other Gentianaceae, 
with the exception of Bartonia and Pleurogyne ; and as this 
last-named genus belongs to the Sweertieae, this is another 
indication that our plant is related to this group. The ovules 
are anatropous and monochlamydeous, and the funiculus is 
rather long. Occasionally, however, we have observed that 
some rudimentary ovules were atropous, and seemed destitute 
of any integument, thus resembling those of the genus Voyria. 
The foliage shows a marked uniformity as regards shape 
and structure. The leaves are opposite, excepting those 
at the base of the stem, which are sometimes alternate. 
This, however, is usually due to an occasionally forced 
curvature of the stem while protruding from the soil. The 
shape of the leaves is spatulate, this form predominating in 
the stem-leaves, the • bracts, and even in the calyx-leaves. 
At the base of the stem they are sometimes more or less 
scale-like. The position of the leaves is somewhat singular, 
standing in a vertical position and being often closely ap- 
pressed to the stem and flowers, in which latter respect this 
plant shows a certain resemblance to the Orobancheae. The 
colour of the leaves is also characteristic, being of a deep 
purple hue, with only a slight shade of green. As we have 
before stated, several writers have expressed the idea that 
Obolaria may be partly or entirely destitute of chlorophyll. 
The colouration is due to the large amount of anthocyan 
dissolved in the cell-sap of the epidermis and present in the 
greater part of that tissue. In this way the chlorophyll 
is almost entirely concealed, since only the mesophyll is 
chlorophyll-bearing. By immersing the leaves in strong 
