V. CRYPTONEMIACE^. 177 



Plate XXVIII. A. Fig. 1. Gigartina microphjUa ; the natural size. Fig. 2, 

 small portion of the lamina, with four fertile, soriferous papilkc ; magnijied. Fig. 

 3, section of a papilla, through a sorus, and 4, a tetraspore ; both highly magnijied. 



5. Gigartina spinosa, Kutz. ; frond somewhat channelled below, thick, cuneate 

 at the base, linear-lanceolate, simple or once or t-\vice forked (the segments some- 

 times sub-pinnate) ; the margin fiinged, and the surface densely muricated with 

 mamilliform or filiform, simple or multifid, acute processes, in which the concep- 

 tacles are immersed. Mastocarpus spinosus, KUtz. in Bot. Zeit. 1847,/?. 21. Tridcea 

 stir lata, Harv. in Beech. Voy. p. 409- {Excl. Syn.) Gigartina ornithorhynchos, J.Ag. 

 1849. Sp. Alg. %p. 274. (Tab. XXVIII. B.) 



Hab. California, Douglas ; Coulter, (v. s. in Herb. T. CD.) 



Pwot discoid. Fronds densely tufted, six to eight inches long, flat or somewhat 

 channelled below, rising with a short cylindrical stem, as thick as a crow's quill, 

 which soon becomes flattened, and gradually widens into the base of the linear- 

 lanceolate lamina. Lamina either simple, tapering to both ends, or more frequently 

 once or twice forked, or irregularly 3 — 4 cleft vertically, the segments in the 

 dichotomous varieties cuneate, those of the others more lanceolate and longer. In 

 some specimens the margin is pinnated with lanceolate or linear wing-like lobes an 

 inch or more in length. Both surfaces are bristled with spine-like, obtuse or acute, 

 simple or compound papillae in which the conceptacles are borne. Conceptacles as 

 large as rape-seed, globose, immersed in the middle or towards the end of the 

 papilla;, the subulate apex of which often extends beyond the conceptacle like 

 the bill of a bird. Colour a dark red brown or dull purple. Substance coriaceo- 

 cartilaginous, thick and coarse. In drying it shrinks considerably, and does not 

 adhere to paper. 



I formerly confounded this species with G. stiriata, to which some of the speci- 

 mens bear a near resemblance, but our plant is less thick and much less gelatinous, 

 and appears to be sufficiently characterised. 



Plate XXVIII. B. Fig. 1. Gigartina sjnnosa ; the natural size. Fig. 2, a 

 compound papilla, bearing several conceptacles ; magnified. Fig. 3, segment of a 

 thin section of a conceptacle, shewing a portion of the external wall and of the 

 compound nucleus ; fig. 4, spores from the same ; both highly magnified. 



6. Gigartina exasperata, Bail, and Harv. ; frond stipitate ; stipes expanding 

 into a coriaceo-membranaceous, broadly lanceolate, entire frond, incrassated at the 

 margin, eroso-dentate and with marginal lobules, both surfaces densely muricated 

 with simple or branched spinous processes in which the conceptacles are lodged. 

 Bail, and Harv. in Bot. Expl. Exped. 



Hab. Fort Nesqually, Puget's Sound, Captain Wilkes, (v. s. in Herb. Expl. Exp.) 

 VOL. rv. — art. 5. A a 



