NO. 1 DAWSON : MARINE RED ALGAE OF PACIFIC MEXICO 39 



These plants are not clearly identifiable with any recorded species, 

 but it seems best, awaiting monographic treatment, to refer them to the 

 Liagora ceranoides complex and to point out two distinctive features, 

 namely, the "cell complex" at the base of the cystocarp (as in L. decus- 

 sata Mont.) and the very regular branching. In habit the plants suggest 

 superficially a dwarf form of L. californica with which it grovi^s, al- 

 though the branching is more approximate and regular throughout and 

 it lacks the characteristic reddish branch-tips of L. californica. 



Liagora magniinvolucra sp. nov 

 Plate 3, figs. 1-11 ; Plate 16, fig. 2 



Thallis 1.5-4.0 mm. altis, circa 1 mm. diametro, dichotomis, ramulis 

 irregularibus pinnatis; calcificatione plerumque extraperipherali ; dio- 

 eciis; antheridiis rosulatis subcapitatis ; ramis carpogonialibus uni- vel 

 etiam bicellularibus ante fertilisationem ; gonimoblasto rosulam hemi- 

 spaericalem efficiente filamentorum ramosorum carposporas terminaliter 

 lateraliterque ferentium, subter cinctorum involucro prominenti fila- 

 mentorum longorum, tenuium, ascendentium. 



Thalli saxicolous, 15-40 mm. high, whitish-farinaceous, cylindrical, 

 about 1 mm. in diameter or less, 1-3 main branches from a small, discoid 

 attachment, dichotomously branched with irregularly alternate short, 

 pinnate branchlets 1-3 mm. long; calcification mainly extraperipheral ; 

 assimilatory filaments somewhat moniliform, with long fusiform cells in 

 inner parts, and short ovate or subclavate cells in outer parts, 7-12 ft in 

 diameter; plants dioecious; antheridia borne on short pedicels, clustered 

 subcapitately on ends of assimilatory filaments ; carpogonial branches 

 small, inconspicous, 1-2 celled before fertilization, 25-30 fi long exclu- 

 sive of the trichogyne, dividing transversely into 2-4 cells after fertiliza- 

 tion and becoming enveloped by more or less contorted steril, involucral 

 filaments which start their growth before fertilization; gonimoblast 

 developing apparently from uppermost cell of divided, fertilized carpo- 

 gonium, forming a hemispherical cluster of branched filaments bearing 

 carpospores terminally and laterally, surrounded from below by an in- 

 volucre of long slender, ascending filaments. 



Type: Holotype is Dawson 3386, Nov. 9, 1946, on sheet 50509, 

 including vial 1654 and slides 946-951, in HAHF. 



Type locality: Intertidal rocky shore, Cabeza Ballena, Baja 

 California. 



Additional material: D. 3220, Nov. 7, 1946, Punta Palmilla, 



