272 Rhodora [NOVEMBER 
monly are exceptionally vigorous. An interesting instance of return 
to an ancestral character of higher grade is described and illustrated 
by Dr. E. C. Jeffrey in his account of the resin ducts of Seguoia. 
The primitive structure reappeared where the food supply had been 
increased and growth had been stimulated as the result of a wound. 
The foregoing facts are representative of a considerable body of 
data ! which might be brought forward in support of certain general 
statements to which I may give the following form: (1) Reversions, 
in either an ascending or a descending direction, are sometimes 
occasioned in plants by a deficiency of the food materials supplied 
to developing parts; and (2) Reversions, in either direction, are 
sometimes occasioned by a superabundant food-supply in developing 
parts. 
Ames BOTANICAL LABORATORY, North Easton, Massachusetts. 
ASPLENIUM EBENEUM PROLIFERUM. 
C. E. WATERS. 
THE most familiar instance of a fern with proliferous fronds is 
the walking-fern (Camptosorus). The greatly prolonged tip of the 
frond is pushed into the moss on the surface of the rock, and a 
young plant is developed. At first the tip thickens, then rootlets 
start out, and finally the small fronds appear. A tropical species 
(Polystichum Plaschnickianum) has almost the same outline of frond, 
and the same method of reproduction as the walking-fern. Scott's 
spleenwort (Asplenium ebenoides), which has now been definitely 
shown to be a cross between Asf/. ebeneum and Camptosorus, is occa- 
sionally seen with young plants at the tip of the frond, or even of 
the pinnae, a trait which has evidently been inherited from the walk- 
ing fern. It is also said that the closely related Asf/. pinnatifidum is 
at times proliferous. 
None of our other ferns has this trait, unless we except the bulbs 
! Dr. R. T. Jackson, in a memoir too little known to botanists, has described a 
large number of instances of localized reversionary stages in plants and animals. 
This contribution to the subject of reversion is an extremely important one. Dr. 
Jackson recognizes the dependence of reversionary forms upon conditions of nutri- 
tion and growth. Memoirs Boston Society of Natural History, vol. 5, no. 4, 1899. 
