1908] JEFF REY—FOLIAR GAPS 247 
very far from being realized in Tmesipteris as described by Miss 
YKES. ‘The conditions are in fact the same as those found in the 
corresponding region of the stem in Phylloglossum. Miss SyKEs 
has been so good as to loan her sections, and the series, although 
hot complete, vouch for the general accuracy of her figures. One 
fact of importance appears, however, to have escaped her notice, 
although it is clearly indicated in the sections, namely, that in every 
case the outgoing strands of appendages originated opposite the 
strands of the central cylinder and did not subtend any gap aé their 
point of origin, although some of them by a subsequent oblique course, 
as in Phylloglossum, seemed to subtend the stelar gaps. Appearances 
of this kind have been brought to the attention of Professor Bower, 
and he figures one such section on page 420 and again on page 487 of 
his recent work.° He expresses the opinion that his figure overthrows 
the hypothesis of JEFFREY on the lycopsid side. He further adds in 
a footnote: “The Botryopterideae are not phyllosiphonic; thus 
the anatomical distinction of JerFrEy breaks down on both sides.” 
In this added statement he is even less happy than in the original one, 
for he is apparently unaware that ferns with a protostelic central 
cylinder cannot possibly be phyllosiphonic, that is, possess foliar 
gaps. In all of the Botryopterideae in which the origin of the foliar 
strands has yet been described the central cylinder is protostelic. 
Professor Bower is in general not entirely at home in discussing 
anatomical facts. As a further example of this, may be cited his 
Statement that Alsophila excelsa, as described by GWYNNE-VAUGHAN, 
shows a “transition from the cladosiphonic to the phyllosiphonic” 
Condition in the young plant. Professor TANSLEY in a review of 
Professor BowER’s book?° very properly criticizes this singular mis- 
understanding in the following words: “Mr. GwyNNE-VAUGHAN 
will be probably surprised to learn that he has shown a ‘transition 
the cladosiphonic to the phyllosiphonic’ state in Alsophila 
excelsa. What really exists, of course, is a transition from protostely 
0 siphonostely, and protostely is not a monopoly of the microphyl- 
lous forms, but is found equally among the primitive ferns.” It 
Cannot be too strongly emphasized that, especially in difficult cases, 
® The origin of a land flora. London. 1908. : 
*° New Phytologist 7:126. 1908. 
