98 Lady Isabel Browne. 
alternation pre-existing vegetative parts became in the phylogeny 
sporangiferous ; but even the staunchest defender of the homologous 
origin of the sporophyte may well hesitate to assert that such highly 
organized structures as the sterile lobes of the Sphenophyllaceous 
sporophyll became sporangiferous. Dr. Scott adduces as an 
analogy the sporangia “commonly present” ( 8 ) on the frond of 
Botrychium. Professor Bower repeats this comparison in his 
latest publication (4). To this analogy two objections may be made. 
In the first place it seems a slight over-statement to say that 
sporangia are commonly present on the frond (as opposed to the 
spike) of Botrychium. Professor Bower himself, after a perusal of 
the literature on the subject and an examination of numerous 
specimens at Kew and at the British Museum, came to the 
conclusion that Botrychium lunaria was the most variable species 
(2). But even of this species he says “ . . . . however, I should wish 
to emphasize again the fact that in Botrychium lunaria, as collected 
in any average locality, the large majority of specimens show the 
sterile frond to be normally sterile, and the fertile spike to be 
normally fertile; that even in this species which appears to be the 
most variable in this respect, the phenomena above referred to are 
exceptional, and are, in my opinion, to be classed as abnormalities ; 
while in other species of the genus, especially in the large-leaved 
forms, they are, if existent at all, so rare that they are seldom or 
never represented in herbaria, or recorded in the books ” (2). Dr. 
Scott himself points out that in Botrychium “ . . . there is still a 
marked difference between the frond and the spike, whereas in 
Sphenophyllum fertile, so far as the material allows of a decision, 
the dorsal and ventral lobes appear to have been perfectly similar 
to one another, though, with better material some minor differences 
may possibly be detected ” ( 8 ). If the sporangia on the usually 
sterile frond of Botrychium are abnormal the analogy with 
Sphenophyllum fertile loses in force, for though it has recently 
been argued that “ sports —or the sudden appearance of exceptional 
characters may be perpetuated, under natural conditions, in the 
descendants of the forms producing them, this is by no means 
proved (13), and though we know that sporangia may and do appear 
as abnormalities on normally sterile parts, yet there is no proof 
that they have, in nature , been retained by the descendants of 
these malformed plants. On the other hand highly organized 
plants often show sterilization of sporangiferous parts. In any 
case, there is at least a probability that, if the sporangia on the 
