Notes. 
443 
raised, the less likely is it that two will be alike, yet this occasionally 
happens, notably in the case of a very curious and distinct variety 
of Athyrium ; and such singular examples convinced me that the 
duplication is to be accounted for by origin from one and the same 
prothallus. To test this a number of prothalli resulting from the 
sowing of a mixture of varieties of Athyrium , and also a similar 
number of Scolopendrium were transplanted singly a quarter of an 
inch apart, so that it was possible to divide a prothallus into several 
divisions at the time when the first fronds were springing up. It is 
not easy to detect the prothallus at the right moment ; because, as the 
frond appears the prothallus dies away; yet the decay of the pro- 
thallus is not always as rapid as the growth of the frond, especially 
where the prothallus has a vigorous growth. 
A number of these prothalli of both Athyrium and Scolopendrium 
were divided ; in the case of the latter I succeeded in dividing in twelve 
instances a prothallus into two plants, and in four instances into three. 
In several instances where there was great vigour of growth, two 
prothalli had grown together and formed a complete interwoven mass 
that could not be separated, and had become to all intents and 
purposes one prothallus from which sprang up fronds having the 
same characters. In the case of these intergrown prothalli in two 
instances they have been divided into four plants, in two into five, in 
one into seven, and in one instance as many as ten plants (unmis- 
takably alike) were divided from the double prothallus. Though yet 
small they cannot fail when mature to resemble each other in a greater 
or less degree. 
If a number of prothalli are grown thickly together there is less 
vigour, they do not seem to blend or grow to any great size before 
the fronds appear, and in these circumstances no two of the resultant 
ferns are alike ; it is, however, apparent that they have been generally 
impregnated, i. e. from all the varieties, because the young ferns 
consist of a series of plants that show a gradation of the forms of the 
varieties sown together, i. e. a series of plants having characters 
intermediate between the varieties experimented upon. 
It is certain, then, that more than one plant can be produced from 
one prothallus, and these have a striking likeness to each other; 
and further, if two prothalli are allowed to grow together, they will 
affect each other, and produce plants having a strong resemblance to 
each other. We are speaking of the plants in their infant state, as none 
