Bower . — Studies in the Phytogeny of the Filicoles . 273 
In the Mertensia section observations were made on G. Bancroftii , Bl. } 
glauca , Hk., flabellata, Br., Cunninghamii , Hvn.furcata, L., owhyhensis , Hk., 
flagellaris , Spr., vestita, Bl., and Bl. In all of them both scales 
and hairs were present, the former especially upon the circinate leaf-apices. 
The scales vary, being large and broad in 6\ Bancroftii , but only narrow in 
G . flagellaris and vestita , while in the latter the hairs are soft and fluffy, of 
the type to be described in £. linearis. Thus, though Mertensia is, as 
a whole, of less xerophytic habit than Eu-Gleichenia , both hairs and scales 
are general, especially on the circinate leaf-apices. 
But in § 3, Gleichenia pectinata , and § 4, Gleichenia linearis , no scales 
are found. They stand in this character apart apparently from the whole 
of the rest of the genus. Hairs are present in both, and they are of the 
tufted type, branching near to the base. In G. linearis these are of a softer 
texture, but in G. pectinata they are stiff and brown, with their peg-like 
branches often reflexed. These hairs, especially those near the insertion of 
the leaf on the axis, are long and curved, and coarse in texture. Each of 
them with its tuft of stiff branches is borne on the end of a rather 
massive emergence, which is a firm multicellular outgrowth. But the hair 
is readily broken away from its tip ; the emergence then remains as 
shown in PI. XXX, Fig. A, in the case of the two lower emergences. And as 
these are numerous and relatively large, they give to the rhizome and the 
base of the leaf that prickly character which is often seen about the base of 
the leaf in Alsophila , Hemitelia , and Cyathea , though here it is on a smaller 
scale. The prickles in these latter plants bear each a ramentum when 
young, and this may be seen with special clearness in the case of the large, 
more or less isolated scales borne on the young leaf of Hemitelia horrida 
(PI. XXX, Fig. B). There can be little doubt that the structures in question 
in Gleichenia pectinata and in the Cyatheaceae are essentially comparable one 
with another ; in that case, those of Gleichenia may be held as a prototype 
of the larger emergences of the Cyatheaceae. See PL XXXIII. 
It appears from the above observations that the two species of 
Gleichenia , which are outstanding in other characters from the rest of the 
genus, are also exceptional in showing the more primitive type of dermal 
appendages only, viz. hairs and no scales. Their aloofness from the rest 
of the genus is further indicated by their anatomy. It will suffice here to 
quote briefly from the conclusions which have been arrived at on the basis 
of comparison of their vascular tissues. 1 Tansley sums up his discussion of 
the anatomy of Gleichenia thus ( 1 . c., p. 46) : ‘We are therefore led to the 
conclusion that such a form as G. flabellata , on the whole, represents the 
most primitive type of the genus. ’ As regards G. linearis he remarks 
(p. 41) that it ‘stands apart from the other Mertensias being ‘ intermediate 
1 Tansley : Lectures on the Evolution of the Filicinean Vascular System, iv, p. 40, &c. Boodle : 
Ann. of Bot., xv, p. 703, and xxiii, p. 419. 
