Note on Abnormal Sporocarp of Salvinia natans. 
BY 
ALFRED J. GRAY; MA Bae, 
With Plate XLVIII. 
This sporocarp, remarkable in that it contains both mega- 
and microsporangia, was found among: material supplied at the 
Royal Botanic Garden, Edinburgh, to the class of Advanced 
Practical Botany. 
Normally the Hydropteridez, which are heterosporous, have 
their microsporangia and megasporangia in different sporocarps, 
which in Sa/vinza are externally indistinguishable, but in A zo/la 
are quite distinct. Yet in 4 zol/a the two kinds of sporocarps can 
be traced back to one type, whilst in the case of Sa/vinza there 
has been an almost entire lack of evidence of common origin. 
In the microsori of Azo//a, the megasporangium aborts at an 
early stage. In the megasori, on the other hand, only the mega- 
sporangium develops, but there are found at later stages of 
development primordia of microsporangia, which abort. Azo/la 
thus shows what we may take to be the stage of separation of the 
original hemaphrodite sori into male and female ones. 
In the male sorus of Sa/vznza, on the contrary, we do not find 
aborted microsporangia, nor aborted megasporangia in the female 
sorus. But in my specimen we have an example of the primitive 
stage which is more closely approached by Azod/a, and the value 
of the evidence is strengthened by the close relationship between 
the two. It is easy to understand the cause of the development, 
for, as Goebel! points out, the separation of microsporangia and 
megasporangia favours cross-fertilisation. 
So far as I am aware, this particular abnormality has been 
only once before observed. It is recorded by Guebel? :—“ We 
} Goebel, Organography of Plants, vol. ii. (1905), p. 487, footnote 6. 
2 Goebel, Zc. 
[Notes, R.B,G., Edin., No. XX, March 1909.) 
