Abnormal Prothalli of Pinus sylvestris. 
BY 
MARY BARTHOLOMEW. 
With Plate XLIX. ’ 
When studying the life history of Pzzus sylvestris recently in 
the Laboratory of the Royal Botanic Garden, I found in a hand- 
made section of an ovule the structure shown in Plate xlix., 
Fig. A. It resembles in its features that of an ovule described 
and figured some years ago by Professor Bretland Farmer,' but 
my specimen shows certain differences, and in any case the 
occurrence of anomalies of the kind have been recorded so 
seldom that a notice of this one may not be superfluous. 
The prominent feature in the specimen is the occurrence of 
a pair of archegonia, Fig. A,¢,, not quite at the same level 
at the chalazal end of the embryosac, and of a single one, a,, 
at the micropylar end. But closer examination shows that the 
prothallar body in which they occur is not normal. In Fig. A, 
there is visible at s, a.distinct lobing of the mass, and passing 
downwards in the figure, ze, towards the micropylar end 
from this indentation, there is an evident line of demarcation 
between a micropylar and a chalazal portion of the prothallar 
body. At s, the separation of the two is so definite that there is 
a space between them, but elsewhere in the section, at s,, for . 
example, there is no break in continuity between the tissues of 
the prothallar masses, although there is a difference in the size of 
the cells at their point of junction as compared with those in the 
rest of the mass. 
We may assume, it seems to me, that there are here two pro- 
1 Farmer, on the occurrence of two Prothallia in the Embryosac of Pinus, 
Ann. of Bot. VI (1892). 
(Notes, R.B.G., Edin., No. XX, March 1909. } 
