238 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 12 



Ahnfeltia Svensonii n. sp.^^^' ^^^ 



Plate 77, Fig. 2 



Plants tufted, to 7 cm tall, dark red, blackening on drying, the surface 

 dull, firmly fleshy, terete or slightly compressed at the forkings, closely 

 and divaricately dichotomous or rarely polychotomous, below somewhat 

 proh'ferous, the segments 5-10 mm long, 0.7-2.0 mm diam., somewhat 

 tapered upwardly, the tips rather obtuse; structurally the axis in section 

 showing a large medulla of subparenchj'^matous aspect with firm cell walls 

 surrounded by a narrow cortex of short cylindrical cells in radial rows of 

 3-4 cells' depth; cystocarps scattered, somewhat projecting, often occu- 

 pying a large part of the diameter of the branch, the carpospore mass 

 immersed, without any sterile base or center, with no defined pericarp, 

 but with a thicker cortex above it which eventually breaks down to a 

 large irregular pore. 



This plant has somewhat the habit of Howe's A. Durvillaei v. impli- 

 cata, but the branching tends to be more irregular and it is a slenderer 

 and softer plant, the branches on drying often becoming quite flat. It is 

 likewise more slender and less horny than those which the writer tenta- 

 tively refers to A. gigartinoides J. Agardh. 



Ecuador: Archipielago de Colon, on littoral rocks at Black Beach 

 Anchorage, I. Santa Maria, no. 34-251 (TYPE), 17 Jan. 1934. 



Ahnfeltia gigartinoides J. Agardh, prox. 



Plants to 3 cm tall, tough, horny, dull reddish purple or blackish, 

 slightly nitent; irregularly dichotomously branched, the branches reach- 

 ing about 1 mm diam., terete, the tips a little tapered. 



These specimens seem a little more regularly branched than Kiitzing 

 figures them (1869, pi. 71) from Liebmann's Mexican material; Setchell 

 & Gardner (1930, p. 152) express a suspicion that the species is simply 

 dwarf A. concinna. 



Mexico: Nayarit, on surf-beaten rocks near high water mark, I. 

 Isabel, no. 34-587, 5 Mar. 1934. Ecuador: Salinas, from south side of 

 Pta. Santa Elena, Schmitt no. 5E, 16 Sept. 1926. 



144 Ahnfeltia Svensonii n. sp. — Planta ad 7 cm altitudine, teres aut ad furcas 

 paululum compressa, arete divaricate dichotoma, segmentis 5-10 mm long., 0.7-2.0 

 mm diam., vix attenuatis, cacuminibus obtusis; cystocarpis dispersis, paululum 

 emmentibus, porum irregularem efficientibus. Planta typica in loco dicto I. Santa 

 Maria, Ecuador, no. 34-251, legit W. R. Taylor no. 34-251, 17 Jan. 1934. 



i-*5 Named in recognition of the botanical exploration of the Galapagos Islands 

 by Dr. Henry K. Svenson in 1930. 



