Ser. RHopOSPERMES. Kam. Spherococcoidea. 
Puate CCLXVIII. 
DELESSERIA CRIS PATULA, tlarv. 
Gun. Cuar. Frond leaf-like, membranous, areolated, symmetrical, simple 
or branched, midribbed. Fructification: 1, hemispherical concep- 
tacles, sessile on the midrib or on a lateral nerve, containing a tuft of 
moniliform spore threads on a basal placenta ; 2, tripartite ¢e¢raspores, 
in definite sori or spots, on the frond or on accessory leaflets.— 
De EssERIA (4g.), in honour of Baron Delessert, a distinguished 
patron of Botany. 
Frons foliacea, membranacea, areolata, symmetrica, simplex v. ramosa, costata. 
Fruct. : 1, coccidia in costa venisque frondis sessilia, hemispherica, fila spori- 
Sera moniliformia a placenta basalt emissa foventia ; 2, tetraspore triangule 
divise, in soros definitos collecte. 
Deesseria crispatula ; frond (of small size) dichotomous, costate; seg- 
ments linear, entire, undulate, obtuse; costa articulated, three-tubed, 
veins none ; sori of tetraspores either in proper leaflets borne on the 
midrib, or in the apices of the forked segments. 
D. crispatula; fronde pusilla dichotoma costata, laciniis pluries furcatis lineari- 
bus integerrimis undulato-crispatis obtusis ; costa articulata 3-siphonia, venis 
nullis, soris in sporophyllis propriis costa enatis v. infra apices laciniarum 
immer sis. 
DELESSERIA crispatula, Harv. in Trans. R. I. Acad. v. 22. p. 548. Harv. 
Alg. Austr. Evsic. n. 
Has. On Cymodocea antarctica. At Fremantle, W. H. H., G. Clifton. 
Gerocr. Distr. Western Australia. 
Descr. Root a minute disc. Fronds single or tufted, 1-3 inches high, and as 
much in the expansion of the branches, repeatedly dichotomous, traversed 
by a very slender, articulated, 3-tubed midrib. acini linear, undulated, 
1-13 line broad, several times forked, either regularly or irregularly, the 
terminal divisions occasionally trifid, always very obtuse or subemarginate. 
In old specimens the midrib, toward the base of the fronds, becomes thick- 
ened and opaque. The membrane of the lamine is very thin and delicate, 
composed of a single stratum of cellules, which are smaller towards the 
margin. ‘The cystocarps are unknown. Sori of ¢etraspores either immersed 
in the apices of the segments, or borne in proper, roundish, or obcordate 
sporophylla, rising from the midrib. The colour is a pale rose-red, soon 
