CARUNCULES OR STROPHIOLES.—THE NUCLEUS. 339 
in a line with the raphe ; while in the Spurge they are placed 
at the micropyle. Some writers consider these caruncules as 
forms of the aril, of which they then distinguish four varieties, 
namely :—1. The true arillus, as in Nymplhea (fig. 757, a, a); 
2. The arillode or micropylar arillus, as in Hwonymus (fig. 758); 
3. The raphian arillus, as in Asarum (fig. 760); and 4. The 
chalazal arillus, as in Epilobiwm (fig. 761), where the tuft of 
hairs at one end of the seed is regarded as an aril. Other 
writers again partially adopt these views, and define the carun- 
cules as little protuberances growing from the raphe, and 
therefore originating independently of the funiculus or micro- 
pyle ; hence the caruncules of Milkwort and Spurge would be 
regarded as true or false arils according to their respective origins, 
and the appendages of Asarabacca and Violet would be true 
earuncules. Other botanists again, instead of using the two terms 
strophioles and caruncules as synonymous with each other, apply 
Fie. 759. 
Fig. 759. Ovoid seed of Milkwort (Polygala), with a caruncule at its base 
or hilum.— Fig. 760. Seed of Asarabacca (Asarum), with a caruncule ou 
the side, which is called by some a raphian arillus. Fig. 761, Section 
of the comose seed of Epilobium. The tuft of hairy processes is some- 
times called a chalazal arillus. 
the former term only when the processes proceed from the hilum, 
and the latter to those coming from the micropyle. Altogether, 
there is a great ditference of opinion among botanists, as to the 
application of the terms caruncules and strophioles ; but in this 
country they are more commonly understood in the sense in 
which we have first defined them. 
2. THE Nuctevus or KERNEL ( figs. 36, emb, alb, and 757, nN). 
In order to understand the structure of the body of the seed, or, 
as it is commonly termed, the nucleus, we must brieHy narrate 
the changes which the nucellus of the ovule undergoes after the 
process of fertilisation has been effected. We have already 
stated, that at an early period before impregnation has taken 
place, a quantity of protoplasmic matter of a semi-fluid nature 
is present in the embryo-sac. Very soon after fertilisation has 
been accomplished in the Angiospermia, frequently even before 
Z2 
