12 2 
The Ohio Naturalist. 
[Vol. VII, No. 6, 
oratory. A piece of damp, decayed wood should be selected 
with a few crevices in it under which the insects may secrete 
themselves. Put the insects in a good sized straight necked 
bottle with a few bits of decayed leaves and dirt in the bottom. 
The wood should be wedged in tight enough so that it will not 
roll around and crush the insects. By keeping the wood a little 
moist all of the time, and in a dark place most Thysanura will 
thrive apparently quite as well as in their natural surroundings. 
THE DEVELOPMENT OF THE SPORANGIUM OF EQUISETUM 
HYEMALE.* 
Lon A Hawkins. 
The sporangium of Equisetum has been the subject of con¬ 
siderable study. The first work of importance was by Hof- 
meister who seems to refer the whole of the sporangium to a 
single cell. Later Russow while verifying many of Hofmeister’s 
statements did not agme to this, but considered it to be of the 
eusporangiate type, the sporogenous tissue as arising from the 
division of a single cell but part of the walls and tapetum coming 
from the surrounding tissue. This is now the generally accepted 
view. 
Goebel (1) gives an account of the development of the 
sporangium of E. palustre or E. limosum which he illustrates with 
two figures. According to this description it seems that the first 
division of the sporangial initial is periclinal and separates the 
primary sporogenous cell from the primary wall cell. In sub¬ 
sequent development the primary sporogenous cell divides 
much more rapidly than the other and we have a large mass of 
sporogenous tissue formed while a segment of the rather thin 
wall of the sporangium is all that comes from the primary wall 
cell. 
This is one of the points where Bower (2) disagrees with 
Goebel. In his study of E. arevense and E. limosum he 
came to the conclusion that Equisetum is eusporangiate; that 
the contents of the sporangium are ultimately referable to a 
single initial; that the first division is periclinal, the inner cell 
and part of the outer going to form spores; and that the sporo¬ 
genous tissue cannot be referred to a single cell as Goebel holds. 
Campbell (3) does not seem to agree with Bower either as to 
the location of the superficial initial or as to its subsequent devel¬ 
opment. His account agrees more closely with that of Goebel. 
There appears no statement of the species he studied but it was 
probably E. telmateia. 
* Contributions from the Botanical Laboratory of Ohio State 
L T niversitv XXX. 
