NO. 1 TAYLOR: PACIFIC MARINE ALGAE 267 



Platythamnion reversum (Setch. & Gard.) Kylin, v. laxum n. v.'^^ 



Plants to 13 cm tall, the axis sparingly divided, the upper branching 

 closer and complanate; the ultimate branches bearing divaricate-divided 

 branchlets on the upper and lower sides, those on the latter, or abaxial, 

 side sometimes the larger, those on the faces obsolescent, but v^^hen present 

 on the lower segments, subsimple. 



These plants appear to represent a deep water form of P. reversum 

 (Setchell & Gardner) Kylin (1925, p. 54, fig. 34d-f), with the so-called 

 "transversal" or facial branchlets obsolescent on the small ultimate seg- 

 ments. 



Ecuador: Archipielago de Colon, dredged at sta. 169 off Academy 

 Bay, I. Santa Cruz, no. 34-319 (cystocarpic, TYPE), 20 Jan. 1934. 

 Ibid.j dredged from 55 meters off Post Office Bay, I. Santa Maria, no. 

 34-371, 29 Jan. 1934. 



PLEONOSPORIUM Nageli, 1861 



Pleonosporium complanatum n. sp.i*^^ 

 Plate 86, Fig. 1 



Plants to 15 cm tall (or more?), rose pink, soft, branching alternate 

 and complanate in the lesser divisions; growth from the main apices by 

 successive slightly oblique divisions, the young segments subequal; the 

 chief axes near the base to 275 fi diam., the cells to 1.5-1.8 mm long, often 

 with a few slender corticating filaments on the surface but these some- 

 times absent ; chief axes bearing numerous alternate branches of equal or 

 greater length and similar structure; secondaiy branches 1-2 cm long, 

 sometimes continuing as tertiary chief axes, closely alternately and com- 

 planately beset with lesser branches and branchlets, the antepenultimate 

 to about 5 mm long, somewhat zigzag, about 50-72 fx diam., the lowest 



167 Platythamnion reversum v. laxum n. v. — Planta laxa, axe sparse diviso, 

 ramificatione superiore confertiore complanataque; ramis ultimis in lateribus 

 superioribus inferioribusque (vel abaxialibus) ramulos divaricato-divisos ferenti- 

 bus, his interdum maioribus; ramulis transversalibus obsolescentibus, subsimplici- 

 bus cum in segmentis inferioribus apparent. Planta typica in loco dicto I. Santa 

 Cruz, Ecuador, legit W. R. Taylor no. 34-319, 20 Jan. 1934. 



168 Pleonosporium complanatum n. sp. — Planta ad 15 cm altitudine, mollis, 

 ramificatione alterna, et, in divisionibus minoribus, complanata; axibus primariis 

 ad 275 \i diam. ad basim, paucis filamentis corticantibus saepe instructis; ramis 

 secundariis ramulos minores ramusculosque arete, alterne, complanataque ferenti- 

 bus; ramusculis infimis et ultimis in latere inferiore cellulae infimae rami penultimi 

 formantis, serie ultima 12-20 \i diam., tereti ; polysporangiis 1-3, praecipue in 

 latere superiore ramusculorum ultimorum ad basim. Planta typica in loco dicto 

 I. Santa Cruz, Ecuador, legit W. R. Taylor no. 34-312, 20 Jan. 1934. 



