464 Bower . — Studies in the Phytogeny of the Filicales. 
is more nearly related to the Cyatheaceae than to Gleicheniaceae : he 
suggests that it is a reduced form as regards its sporangium, and especially 
that the annulus, with its well-known incomplete induration, is a derivative 
from the type of the Cyatheaceae. His discovery of stiff appendages 
(‘ Borsten ’) upon the older prothalli provides a line of parallel comparison, 
for such ‘ Borsten ’ occur also on the prothalli of the Cyatheaceae. While 
welcoming the facts which von Goebel has added, I regret not being able 
to accept his conclusion, and I shall here re-state an alternative opinion, 
already expressed elsewhere (‘Land Flora,’ pp. 571-4). 
It is an unfortunate circumstance that the term ‘Cyatheaceae’ has 
been used in a more extended, as well as in a restricted, sense. Diels 
(Engler u. Prantl, i. 4, p. 113), Christ (‘ Farnkrauter,’ p. 10), and Christensen 
(‘Index Filicum,’ p. xvi.) have all applied it in the more extended sense, so 
as to include the Dicksonieae, the Thyrsopterideae, and the Cyatheae (or 
Alsophileae) — that is, to comprise Gradate Ferns, some with marginal, 
some with superficial sori. But Hooker, in the ‘ Synopsis Filicum ’ (pp. 9 and 
15), separated his Tribe I, Cyatheae, from his Tribe II, Dicksonieae. 
Though he thus separated the main genera of Cyatheoids from the Dick- 
sonioids, he placed the marginal Thyrsopteris with the superficial Cyatheae, 
and such superficial genera as Onoclea and Hypoderris with the marginal 
Dicksonieae. So that still in his system the position of the sori was not 
given its proper diagnostic importance. It will be pointed out later that it 
is essential to keep the distinction between marginal and superficial sori 
clearly in view, if a truly phyletic classification is to be arrived at : and, if 
that be so, clearly the relation of Loxsoma will be with the Schizaeaceae on 
the one hand, and with the Dicksonieae on the other, rather than with the 
Gleicheniaceae or the Cyatheae in the restricted sense. 
Professor von Goebel demonstrates the presence of ‘ Borsten ’ on 
flattened prothallus of Loxsoma. They resemble structurally the stiff dark 
hairs which cover the rhizome of that Fern. He points out that their 
presence on the prothallus is a characteristic of the Cyatheaceae in the 
widest sense , and of some few Polypodiaceae, and that they are recorded 
from no representative of the Gleicheniaceae or Schizaeaceae. In his 
‘ Organographie ’ (p. 41a) he records that these hairs are present in Balantium 
antarcticum , so that they are not diagnostic between the marginal series 
(Dicksonieae) and the superficial (Cyatheae). The fact that they are present 
in Loxsoma may therefore be held as confirming a relationship with the 
marginal series, viz. with the Dicksonieae. But, on the other hand, the 
fact that they are absent from the prothalli of the Gleicheniaceae and 
Schizaeaceae, as also from those of the Osmundaceae, must not 'be held in 
any way to preclude comparisons with those relatively primitive types in 
respect of other characters, and particularly of those of the sorus and 
sporangium. 
