T22 BOTANICAL GAZETTE [OCTOBER 
Secondly, central loculi as well as peripheral ones occur in the new 
form. A third outstanding difference is the absence of any evidence 
that the sporange underwent apical dehiscence, which is almost 
universally the case in species of Telangium, whether Lower Carbon- 
iferous (for example, 7. affine) or Upper Carboniferous (for example, 
T. Scottii, etc.). The only exception known to me is a species* 
described by Natuorst (11). A fourth outstanding difference 
from Telangium Scottii (the only species so far described with struc- 
ture preserved) is the presence in the new form of water storage 
tracheids, which, although few in the normal specimens, are very 
abundant in the partially sterile specimens. Lastly, a character 
is found which at first sight seems of minor importance. The new 
sporange retains the twofold cortical sclerotic plates which form 
so characteristic a feature of the cortex of Heterangium stem and 
petiole. It is this latter feature which the writer regards as irrefu- 
table evidence of the safe attribution of these microsporangia to 
Heterangium Grievii, with which they have invariably been found 
associated. Although, therefore, the sporange has the same claim 
to the name of the parent plant as either stem or petiole, it has 
been found convenient to refer to it under the name of Heterotheca 
Grievii. 
Diacnosis.—I have founded the form genus Heterotheca for 
the reception of such microsporangia as resemble Telangium in 
form and possibly in insertion, but possess vertical sclerotic plates 
in their periphery and horizontal sclerotic plates deeper down in 
the cortex, like the vegetative organs of Heterangium Grievit. The 
loculi are not confined to the periphery, but central ones also occur. 
The specific name of the form now described is that of the 
parent plant. 
Form, anatomical structure, and grouping of specimens 
Form.—The form of the sporange can be deduced from the 
various series of sections through single specimens. Some of these 
have been plotted out to scale in text figs. r and 2. These show 
* This species, of which sd type saseacene was edie by ARBER (1) under the name 
of Carpolithus Nathorstii, ma of Telangium, owing to NATHORST ’S 
discovery of its longitudinal loculi filled with micro spores. The plate referred to 
exhibits what was possibly approximately the habit of Heterotheca Grievii. 
