Studies in Apospory and Apogamy in Ferns 
BY 
J. BRETLAND FARMER, D.Sc., F.R.S., 
AND 
L. DIGB^ 
With Plates XVI-XX. 
T HE study of monstrosities has played a varying part in the growth 
of our ideas on morphology. At one time it has seemed as if 
teratology held the clues to the solution of all morphological problems, 
whilst at another time it has so sunk in estimation as to be looked on as 
little better than trifling and foolishness. One of the chief obstacles in the 
way of correctly weighing the value of teratological evidence lies in the 
difficulty of deciding, in any given instance, how far one is justified in 
reading a phylogenetic significance into an ontogenetic fact. It is probably 
true, for those who feel able to settle difficulties on a priori grounds — who 
belong to the school of transcendental morphologists — that ‘ Les mon- 
struosites favoriseraient egalement tous les reves de Timagination, et . . . on 
verrait en elles tout ce qu’on voudrait y voir’ (A. de St. Hilaire). But 
it is equally true that there is another and more profitable way of dealing 
with abnormalities. They may be regarded as the results of interference 
with ordinary reactions on the proper sequence of which that which we 
call * normal ’ development depends. The introduction of experiment into 
teratological inquiry has done much to put the subject on a proper footing, 
and to encourage the hope that by its means we may be able to penetrate 
somewhat into the physiological workshops where morphological problems 
are constructed. 
Amongst these problems none, perhaps, are of greater interest than 
those concerning sexuality. Two aspects of this matter have to be kept 
in view, firstly the facts and meaning of the sexual fusion itself, and 
secondly that correlative process of meiosis, 1 which is so intimately con- 
1 See Farmer and Moore, On the Maiotic Phase (Reduction-divisions) in Animals and Plants. 
Q. J. M. S., vol. xlviii, 1905. The terms ‘ Maiosis ’ and ‘ Maiotic’ should have been written Meiosis , 
Meiotic, respectively. This form of the words is adopted in the present paper. 
By the term meiosis, or meiotic phase, is meant that nuclear change which is concerned in the 
reduction in number of the chromosomes. Two mitoses are always involved, but the change in question 
[Annals of Botany, Vol. XXI. No. LXXXII. April, 1907.] 
