222 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 12 



AGARDHIELLA Schmitz, 1889 



Plants branching, the branches terete, tapering moderately firm; 

 medulla diffuse, filamentous, with a soft jelly between the filaments, the 

 inner cortical cells large, colorless, the outer ones small and bearing 

 chromatophores; tetrasporangia formed beneath the surface of the cortex, 

 zonate; spermatangia covering large areas of the cortex of small plants, 

 each cortical cell bearing three to five supporting cells, which each carry 

 two or three spermatangia; cystocarps large, the carpospore mass in the 

 inner cortex and medulla, distending the outer cortex so as to project 

 slightly, the carpospores terminal on the gonimoblasts, discharging by a 

 pore. 



Agardhiella tenera (J. Agardh) Schmitz 



Taylor 1937, p. 286, pi. 38, fig. 4, pi. 41, fig. 2, pi. 59, fig. 9. 



There is nothing distinctive about the figures or description of A. 

 mexicana Dawson (1943, p. 288, pi. 69, fig. 1). A conspicuous main axis 

 is often wanting in the eastern form. Tetrasporic plants of A. tenera 

 develop abundant "spinulose projections" when the tetraspores genninate 

 in situ. This is a common phenomenon in southern New England waters. 



Mexico: Is. Revilla Gigedo, an attenuate form dredged from 45 

 meters' depth at sta. 919 near I. Clarion, no. 39-34, 17 Mar. 1939. 

 Ecuador : Archipielago de Colon, dredged from 33 meters' depth at sta. 

 157, Tagus Cove, I. Isabela, no. 34-183, 15 Jan. 1934. Ibid., dredged 

 from 27 meters off Tost Office Bay, I. Santa Maria, no. 34-229, 19 Jan. 

 1934. Ibid., from 55 meters, no. 34-385 (tetrasporic and carposporic), 

 29 Jan. 1934. Ibid., dredged from a rocky bottom at 37-55 meters near 

 an islet in Gardner Bay, I. Espafiola, no. 34-411 (cystocarpic), 31 Jan. 

 1934. 



SARGODIOTHECAKylin, 1932 

 Thallus flat, angularly divided ; medulla somewhat loose, of compara- 

 tively thin filaments, the cortex large celled within, smaller celled with- 

 out; tetrasporangia scattered in the outer cortex, zonate; cystocarps scat- 

 tered, the gonimoblasts lying in the medulla surrounding and radiating 

 from a small-celled sterile tissue, the seriate carpospores interspersed with 

 isolated sterile strands, the whole somewhat unilaterally protuberant, dis- 

 charging by a pore. 



KEY TO SPECIES 

 1. Branches not foliaceous, generally less than 1 cm wide . . 2 



1. Branches wider, reaching 2-3 cm below the forks . S. ecuadoreana 



2. Branches thin, commonly over 5 mm wide; stalk cylindrical . 

 S. tenuis 



2. Branches extremely divergent, fleshy, commonly under 4 mm 



wide ; without distinctive cylindrical stalk . . . . S. divaricata 



