162 BRITISH MARINE ALG. 
seldom attains the dimensions of that species. Fig. 150, represents a 
beautiful form of this species, described by Dr. Harvey as P. Brodiai, 
var. simplex, the fronds of which have stems about ltin. long, expanding 
into beautiful rose-coloured lobes twice or thrice forked, but not usually 
producing another series of segments. This variety is very rare. The 
plant from which our illustration was taken, was gathered by me in Torbay 
this summer (1873). The fronds were about 2in. in length, the colour of 
the stems was a dark brownish-red, that of the leafy portions, brown-red 
tipped with rose-pink. P. palmettoides (Fig. 151 a) is the smallest and the 
rarest of this genus. The fronds, which are numerous, arise from a broad 
fleshy disc. The stem is short and filiform or string-like, about an inch 
high, terminating in a simple or rarely more than once divided leafy 
expansion of a cuneate or wedge-shaped form. These little fronds some- 
times throw out tiny leaflets from their tips or their surfaces. Tetraspores 
are the only form of fructification I have observed on this species, and 
they are contained in transverse sori in the form of an ellipse near the 
tips of the fronds. I took this pretty little species once only, many years 
ago, in the neighbourhood of Plymouth; this season a very pretty form 
of the plant has been taken on the Meadfoot rocks, near Torquay, by 
Mr. and Mrs. Josiah Field. This rare little plant bears a very strong 
resemblance to the early state of P. Brodiwi, from which it may generally 
be distinguished by the much greater expansion of its discoid base, the 
stems being more distinctly separated from each other, and the leafy parts 
of the fronds being a more decided rose colour, that of P. Brodiwi being 
brown-red or inclining to purple. P. membranifolia, Fig 151 6, is much 
more frequently met with than either of the two species just described. 
The fronds vary from 6in. to 10in. high; the stem is filiform or even 
stick-like, but the branches suddenly expand into prettily fan-shaped 
forked or cloven frondlets, which sometimes, but rarely, bear a second 
series of segments. The tubercles of this species are borne on little 
stalks thrown out from the upper side of the branches. Nemathecia, 
which are frequently produced, occupy the principal inner surface of the 
frondlets; they are of a darker tint than the plant, and are of angular 
form, similar in fact to that of the division or frondlet in which they oceur. 
I have taken this species at Shanklin, in Torbay, and at Plymouth. Itis 
-like the rest of this genus, perennial, and fruits in the autumn and winter, 
Most of the species are troublesome to mount on paper, as they are apt 
to shrink in drying and are often very much encrusted with zoophytes 
or some of the calcareous alge. These annoyances are easily scraped 
away while the plants are still in the mounting dish, and when they are 
partially dried, they may be re-floated and mounted on fresh paper, when, 
with good pressing, they will adhere tolerably well; if not, a slight 
application of dissolved isinglass to the under side of the loose or rigid 
parts will secure them permanently. 
The genus Gymnogongrus, from the Greek, soutien ‘exposed wart-like 
excrescence,”’ in reference particularly to the fructification of one of these 
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