332 BOTANICAL GAZETTE [NOVEMBER 
midrib of the leaf, the smaller being the farther removed. Normally 
the stalk of the single sporangium is immediately above the midrib of 
the leaf. 
The origin of such a situation can only be conjectured. Since the 
sporangium of Lycopodium arises from a transverse row of initials, it is 
probable in this case that there 
was a sterilization of arche- 
sporial tissue within this row, 
separating the two ends of the 
row, each of which developed to 
maturity ina practically normal 
manner, producing the two dis- 
tinct and separate sporangia. 
The formation of the “sub- 
archesporial pad” in the spo- 
rangium of Lycopodium may be 
regarded as a sterilization of 
potentially sporogenous tissue, 
which, while not producing 
complete septation of the 
sporangium, is suggestive as 
a prelude to the complete septation which occurs in other forms, such 
as Psilotum, as a result of the sterilization of complete plates of tissue. 
In this case the sterilization may be thought of as having occurred 
so early as to result in two completely distinct sporangia. Whether 
the polysporangiate condition in Pteridophytes may have arisen in a 
similar way is of theoretic interest, the synangium being regarded as 
intermediary between the monosporangiate and the polysporangiate 
conditions. On the other hand, the two sporangia may have arisen from 
two distinct groups of initials. 
OWER, concluding his note on L. rigidum, states that “it shows how 
even the most rigid facts of morphological experience are liable to excep- 
tion, and that this applies equally to spore-bearing members, in cases 
where their forms seem most stereotyped.” 
To summarize, (1) bisporangiate sporophylls in Lycopodium are very 
rare, a single case of each being known in L. rigidum and L. lucidulum; 
(2) the two sporangia may have arisen as a result of very early steriliza- 
tion of archesporial tissue, or from two distinct groups of initials— 
A. W. Dupter, Juniata College, Huntingdon, Pa. 
Fic. I 
