ANATOMY AND AFFINITY OF CERTAIN RARE AND PRIMITIVE FERNS. 365 
being seated on a peg, or several hairs being attached to a mound. Examples are 
given in fig. 1. The dermal appendages of the leaves are tortuous multicellular hairs 
(fig. 3). Their terminal cells are not glandular. The dermal appendages are for the 
most part persistent on the mature axis, but the hairs are retained only on the lower 
surface of the mature pinnse. The circinate immature rachis and pinnae are com- 
pletely hidden by a dense hairy covering. The dermal appendages of the other 
species examined are similar to those of J. scalaris. 
The dermal appendages of the species examined are sufficiently distinctive to 
preclude a close comparison between them and those of any other genus. In 
questions of affinity the evidence provided by dermal appendages is commonly in- 
conclusive, for while marked differences of form of the dermal appendages may exist 
within the limits of a single genus, it is common knowledge that similarity of form 
may characterise the dermal appendages of distinct genera. Dunzinger’s opinion 
that the kinship of Jamesonia and Gymnogramme is demonstrable by a comparison 
of hairs from Jamesonia and G. elongata, Hk. et Grev., and G. myriophylla , Sw., 
cannot be upheld. 
Text-fig. 1. 
Axis. — In a transverse section of the axis above the insertion of the youngest leaf 
the arrangement of tissues may be as in text-fig. 1 (a). The immature stele ( st .) is 
lodged in a mass of thin-walled parenchyma (p.), and the peripheral band of cortex 
is sclerotic (sc.). Further from the apex the entire medulla ( m .) becomes sclerotic. 
A broad neck of sclerenchyma fills the leaf-gap and unites the pith and cortex 
(text-fig. 1 ( b )). A crescent of parenchyma is thus isolated between the convex 
face of the stele and the sclerotic outer cortex. As the point of leaf-insertion is 
approached a new gap appears in the stele (text-fig. 1 (c)), and as the leaf-base 
merges with the axis a band of sclerotic ground-tissue bridges the moat of thin- 
walled cells and links the medulla and cortex through the new gap (text-fig. 1 ( d )). 
On the adaxial side of the undivided leaf-trace the cortical tissue of the leaf-base is 
entirely sclerotic, but a crescent of thin-walled parenchyma lies on the abaxial convex 
face of the trace. This parenchymatous crescent accompanies the leaf-trace through 
the cortex of the stem, and when the leaf-trace is about to unite with the stele and 
close the leaf-gap the parenchyma of leaf-base and axis become confluent (text-fig. 
1 (e), (/)). As the first leaf-gap has been closing the second has widened, and the 
slender bridge of sclerenchyma linking the medulla and cortex has broadened to a 
thick neck. The sclerenchyma of axis and leaf-base is apparently devoid of inter- 
cellular spaces, but the thin-walled parenchyma is well ventilated (fig. 5). The 
sclerotic cells contain much starch, but the parenchyma is full of granular bodies 
which are apparently plastids. The pith and outer cortex are uniformly sclerotic, 
