NO. 1 TAYLOR : PACIFIC MARINE ALGAE 285 



about 15°-45°, the sinuses slightly rounded; tip segments blunt, 3-5 mm 

 broad, rounded or emarginate; growth without a special transversely 

 dividing apical cell; one cell in thickness near the tips, below near the 

 margins to 4 cells thick and near the midline to 6-10 cells thick; veinlets 

 obscure, microscopic, anastomosing; cystocarps frequent, marginal or sub- 

 marginal, about 1 mm diam., prominent. 



This plant in the absence of tetrasporic material cannot be assigned to 

 the segregated genus Acrosorium with certainty. The material, while not 

 abundant, was in excellent condition. 



Ecuador : Archipielago de Colon, infrequent as dredged off Academy 

 Bay, I. Santa Cruz, no. 34-318B (cystocarpic, TYPE), 20 Jan. 1934. 



Acrosorium (?) fragile n. sp.^^^ 



Plate 95, Fig. 2 



Plants to 15 cm tall, epiphytic, below concrescent, above free, flat 

 throughout, delicate in texture and dull rose colored; branching irregu- 

 larly alternate to subdichotomous, rarely opposite, or with short acute 

 adventitious branchlets, the segments 1-3 cm long, 2-5 mm broad, con- 

 siderably narrower in the upper than in the lower segments, strap shaped 

 or a little broader at the top of a segment, the margins entire ; branching 

 generally divaricate at 60°-90°, with rounded sinuses, the tip segments 

 1-2 mm broad, with apices a little tapered and rounded ; growth without 

 a special transversely dividing apical cell, the thallus one cell in thickness 

 above, 2-3 cells thick below; veinlets very obscure, microscopic, anasto- 

 mosing. 



Ample material in excellent condition for study was secured, except 

 that it was all sterile, and consequently no assurance of its segregated 

 generic status could be gained. 



Ecuador: Archipielago de Colon, dredged off Academy Bay, I. 

 Santa Cruz, no. 34-317 (TYPE). 20 Jan. 1934. 



Acrosorium uncinatum (J. Agardh) Kylin 

 Plants 2-5 cm tall, entangled in other algae, branching subdichoto- 

 mous to subpinnate, the branches narrow, 1-3 mm wide, thin, flat, the 

 margin entire, irregular, or with occasional projections, the tips pointed 

 or commonly hooked ; structurally one cell thick except for the irregularly 

 ramifying and anastomosing veins, where it is three cells thick. 



182 Acrosorium fragile n. sp. — Plantae ad 15 cm altitudine, infra concrescentes, 

 supra liberae, delicatae; ramificatione magna ex parte divaricate irregulariter 

 alterna ad subdichotomam, versus partem plantae superiorem aliquantum angus- 

 tata, segmentis 1-3 cm long., 2-5 mm lat., ad cacumina 1-2 mm lat., apicibus 

 paulum teretibus rotundatisque; supra cellulae unius crassitudine, infra 2-3 cellu- 

 larum, venulis obscurissimis microscopicis, anastomosentibusque. Planta typica in 

 loco dicto I. Santa Cruz, Ecuador, legit W. R. Taylor no. 34-317, 20 Jan. 1934. 



