96 Macfarlane—Observations on Some Hybrids 
of parental hair inherited in greatly reduced numbers and of 
much smaller size, and another type inherited in reduced 
numbers, but of exactly the same size. Still further, the 
hybrid inherits bilobed glands from D. zztermedia in moderate 
quantity. Three types of epidermal glandular appendage are 
thus inherited by the hybrid from its parents. 
I do not propose to describe in detail at present all the 
points of floral or fruit and seed structure. The careful 
observations of another season will be needed before exact 
comparisons can be made. It may be said, however, that the 
pollen grains of D. filiformis are richly granular, largest in 
size and measure 56 » across. Those of D. intermedia are 
also granular and plump; they measure 44 # across. Most 
of the hybrid grains are more or less starved or poor in proto- 
plasmic substance. They measure 48-50 yp, so that develop- 
ment of the pollen grain walls has proceeded perfectly, though 
the enclosed fertilizing substance appears to be imperfect. 
The ovules and seeds of both parents matured well, those of 
the hybrid remained small and in most instances developed as 
empty or nearly empty shells. Cultivation and future study 
will demonstrate how far this may be a constant character. 
The naked eye and histological details described above em- 
phasize the position first fully established by the writer,* that 
a hybrid is, as a rule, down to its minutest details, a blended 
reproduction of both parents in which the morphological and 
physiological details of each are reduced by half. In no case 
has it been possible to detect the entire loss in the hybrid of 
some parental condition, and this cannot be too strongly 
insisted on in view of the loose theoretical reasonings often 
indulged in now on questions of heredity. Peculiarities of 
structure, and equally, it seems, of function, are not readily 
lost, but may persist, in a gradually reduced state, in several 
succeeding generations. 
A glance at the comparative results, however, equally 
* Trans. Roy. Soc. Edin. Vol. XXXVII, p. 203. 
