Fig. 171. DELESSERIA ALATA. 
Colour, A deep red. 
Substance. Side-wings membranaceous ; midribs elastic and firm. 
Character of Frond. Stems and branches winged with a delicate membrane on each side ; 
nowhere furnished with distinct leaves. But in luxuriant specimens, the winged 
membrane has side-veins, similar to those of a leaf. Stem compressed ; several 
times forked {dichotomous') ; or excessively but irregularly branched. Margins whole 
(entire). Tips often cleft, and overlapping. 
Measurement, Frond from 3 to 8 inches high. Branches from to ^ of an inch wide. 
Fructification. Of two kinds. 1. A mass of spores in globose capsules^ imbedded in (but pro- 
minent above) the midribs ; towards the extremity of the branchlets. 2. Tetraspores 
imbedded either in minute leaflets springing from the midrib either at or near the 
tips, or in the tips themselves. Leaflets springing from the midribs. 
Habitat. Our coasts generally. On rocks ; the stems of Laminaria digitata, and other large 
algas, and in from four to ten fathoms water. Common. 
So different in the width of the winged membrane that the young student may easily be 
led to suppose he has got hold of a different species in the different varieties. Sometimes 
from the abundance of leaflets growing out of the midribs the whole upper part of the frond 
is thick and bushy. Egfer back to Plate XXXIII. Fig. 1.50, for Delesseria anyustissima, which 
is suspected to be only a narrow variety of D. alata. 
Fig. 172. DELESSERIA HYPOGLOSSUM. 
Colour. A fine pinky-red, soon given out in fresh-water. 
Substance, Delicately membranaceous. 
Character of Frond. Composed entirely of leaves growing from leaves ; the younger from the 
midribs of the older, in several series ; so that the tout ensemble in full-grown speci- 
mens is globose. Leaves linear-lanceolate, tapering at each end ; margins whole 
(entire?). Midribs distinct ; side-veins faintly marked ; transparent. Branchlets 
springing from the midribs. 
Measurement. Most variable. Leaves sometimes of an inch wide ; sometimes \ an inch. 
Fronds from an inch to | a foot high. 
Fructification. Of two kinds. 1. A mass of spores in globose capsules., immersed in (but 
prominent above) the midribs of the leaflets. 2. Tetraspores forming linear groups 
on each side of the midrib. 
Habitat. Our shores generally. On rocks and algse. Not uncommon, though rare in Scotland. 
At Cushendall, Co. Antrim, the frond grows from three to four feet long. But this is a 
very unusual size. Even in the narrowest varieties, however, the character of the species is 
preserved ; i. e. the growth of the leaves from the midribs of others ; a peculiarity the figure 
does not make sufficiently clear, as the leaflets there have the appearance of springing from 
the margins of the preceding set, which is not the case. D. hypoylossvm cannot be con- 
founded with any other plant, with the exception of Delesseria ruscifoUa ; but D. hypoglossum 
is of a brighter colour; thinner; and its leaves are longer and narrower in proportion, and 
pointed instead of obtuse at the tips. For another Delesseria see Plate XL. Fig. 182, where 
the characteristic growth of that species and the present is better given. 
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