Holm.— On Obolaria virginica . 379 
saprophytic, as has been supposed, it might be well to cite 
the principal features which characterize our genus. These 
may be divided into two categories : (1) Such characters as 
it has in common with the autophytic Gentianaceae, and 
(2) the characters by which it is related to the saprophytic 
members of the Gentianaceous family. In the first category 
are the following characters: (1) The shape of the aerial 
leaves is spatulate, not scale-like ; (2) the presence of chloro- 
phyll in great abundance ; (3) the presence of stomata ; 
(4) the ability to produce starch ; (5) the strong development 
of the hadrome in the stem ; (6) the anatropous, monochla- 
mydeous ovules. In the second category, comprising the 
saprophytic characters, are (1) the vertical, appressed leaves ; 
(2) the non-differentiation of the mesophyll ; (3) the imperfect 
root-system, that is, lack of root-hairs, few ramifications, and 
non-development of the primary root ; (4) the root is a 
mycorhiza ; (5) the occurrence of some rudimentary ovules, 
these being atropous and destitute of integuments. 
According to this characterization, it cannot be denied that 
our plant shows a singular position between the Autophytes 
on the one hand and the Saprophytes on the other. The 
structure of the roots would be rather abnormal to an auto- 
phyte, as would be the chlorophyll and the strongly developed 
hadrome to a saprophyte. In considering the characters of 
the saprophytic Gentianaceae, so admirably described by 
Johow, the following differences will be noted: — The sapro- 
phytic Gentianaceae have no chlorophyll, no stomata, and 
no lignified tissues, while all these are found in Obolaria. 
The only features, and these are unimportant, which Obo- 
laria has in common with its saprophytic relatives are the 
non-development of the primary root, lack of root-hairs, and 
the lack of stereome. It grows in soil poor in humus, and 
in localities which are neither shaded nor very moist, con- 
ditions which do not seem especially favourable to Sapro- 
phytes. The saprophytic Gentianeae are all inhabitants of 
moist and shaded places, being found generally among 
decayed leaves or on the trunks of dead trees. Being one 
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