V. CRYPTONEMIACE^. 175 



Root accompanied by creeping, branched fibres which throw up numerous, erect 

 stems. Fronds densely tufted, two to four inches high, from half a line to a line in 

 breadth, nearly flat, but the margins incurved towards one side, making a channel 

 in the middle of the disc ; the stem naked for an inch or more above the base, then 

 forked, the segments either simple or again forking, naked below, closely pinnated 

 or bi-pinnate in the upper half. Pinnm distichous, opposite or irregularly placed, 

 from a quarter to half an inch or more long, very patent, simple or set with divari- 

 cating, spine-like pinnules. The pinnules in some specimens are mere thorn-like 

 ramuli, but in others are multifid, either irregularly so, or somewhat dichotomous, 

 all the ultimate divisions being remarkably squarrose. Apices acute. Conceptades 

 imbedded in the substance of the pinnoB or pinnules, one or more in each, very 

 frequently armed with minute awl-shaped spines, colour very dark blackish purple. 

 Substance cartilaginous. It does not adhere to paper in drying unless previously 

 softened by long steeping in fresh water. 



A well marked species, probably not uncommon on the Pacific coast. 



Plate XXVII. C. Fig. 1. Gigartina canaliculata ; the natural size. Fig. 2, 

 portion of a frond with conceptades ; somewhat magnified. Fig. 3, longitudinal 

 slice of a branch, showing the internal structure ; highly magnified. 



2. Gigartina mollis^ Bail, and Harv. ; frond cartilaginous, piano-compressed, 

 linear, distichous, pinnately branched ; branches alternate or opposite, erect, taper- 

 ing at the base, naked below, pinnated above ; ultimate ramuli narrow, sub-filiform. 

 B. and U. in Bot. Eapl. Exped. 



Hab. Pacific Coast at Puget's Sound, Capt. Wilkes, (v. s. in Herb. Expl. Ex.) 



Frond three to four inches high, from one to two lines in breadth, distichously 

 branched, once, twice, or thrice pinnated, the pinnae (and pinnules) all very erect, 

 naked below, closely set with pinnules above, narrowed to the base and apex, some- 

 times forked and then each division pinnated. Colour purple. Substance cartilagi- 

 nous, soon decomposing if moistened after having once been dried, and then closely 

 adhering to paper in drying. 



Of this I have only seen the few specimens collected in Capt. Wilkes' Expedition. 

 So far as these enable me to speak, the species appears different from any previously 

 described. 



Sect. 2. Mastocarpds, Kiitz. Frond thick., dichotomous or sub-juniiate, the seg- 

 ments flat, widening upwards, cuneate or oblong, sometimes very broad. Conceptades 

 formed in papjilliform processes issuing from both surfaces of the expanded frond. 



3. Gigartina mamillosa, J. Ag. ; frond flattish, channelled, linear, dccompound- 

 dichotomous, fastigiate ; upper segments wedge-shaped, bifid ; papilla; issuing from 

 the disc and margin, tongue-shaped, each containing a single roundish conceptacle. 



