98 Macfarlane—Observations on Some Hybrids 
these have been shown to be reproduced not in blended fash- 
ion, but as distinct structures reduced either in size or number 
or both. The elongated glandular hairs on the sepals of 
D. filiformis, and the sessile two-celled glands ot D. zntermedia 
alike appear in the hybrid. Such a morphological pattern is 
frequent in hybrids whose parents are somewhat removed in 
systematic affinity, and suggests interesting cytological specu- 
lation. For, if every cell in the hybrid be, as its structure 
proclaims it to be, a combined effect of two parental condi- 
tions each reduced by half, some appropriate explanation must 
be given to the special case before us. As yet we have no 
evidence which would militate against the view, and every- 
thing is in favor of it, that every average cell of a hybrid has 
an equal number of chromosomes and half as much chromatic 
substance as is found in each parent. But for the production 
of two such epidermal appendages some special line of devel- 
opment must have been taken by the epidermal cell which 
gave rise to each. The view would be an imperfect one 
which would cause us to suppose that chromosomes repre- 
sentative of one parent were alone present in such epidermal 
cells. It will be more consonant with the principles of 
heredity, if we suppose that at a certain cell centre in the epi- 
dermis, a special growth-potentiality is inherited from one 
parent, that stimulates to the formation of a hair characteristic 
of it, and that while the hereditary influence of the other 
parent, that is devoid of such hairs, is sufficient to reduce or 
check back growth of the hair to at leasi half the size of the 
parental one, it fails to prevent the development of a structure 
peculiar to one parent alone. Neither is there any need to 
suppose that there is a separation or sorting out of chromatic 
elements in the process. Side by side on the same spirem 
thread of the epidermal cell which produces such a hair, 
elements of both parents may exist, and similarly also in each 
cell that contributes to the hair formation. But the decidedly 
reduced size, in the hybrid, of the glandular hairs inherited 
