236 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 12 



prominent, the base contracted, the apex produced and ostiolate, the 

 sterile basal tissue broadly attached to the thallus, connecting with the 

 pericarp by trabeculae across the spore mass. 



Ecuador: Archipielago de Colon, in tufts on surf-beaten rocks, 

 Black Beach Anchorage, I. Santa Maria, nos. 34-261 (cystocarpic), 34- 

 270 (tetrasporic, TYPE), 18 Jan. 1934. 



Phyllophoraceae 



Plants bushy, dichotomously branched, the branches cylindrical to 

 membranous; structurally showing a pseudoparenchymatous medulla and 

 obscurely filamentous cortex of anticlinal cell rows; sporangia in slightly 

 elevated nemathecia, mono- or tetrasporangial, the tetrapartite sporangia 

 being produced in anticlinal series ; spermatangia developed on outgrowths 

 from surface cells; carpogenic branches three celled, borne on supporting 

 auxiliary cells which with other cells of the branch produce sterile out- 

 growths, the carpospores being in irregular masses interwoven with these 

 and within a sterile sheath. 



KEY TO GENERA 



1. Branches broadly strap shaped ; branching complanate Stenogramma 



1. Branches narrow, filiform, terete or a little flattened ... 2 



2. Branches terete Ahnfeltia 



2. Branches compressed, at least at the forks . . . Gymnogongrus 



AHNFELTIA Fries, 1835 



Plants bushy, wiry, dichotomous or unilaterally branched, sometimes 

 proliferous; slender branches terete, of multiaxial growth, the firm 

 medulla of many slender longitudinal filaments, the firm cortex of anti- 

 clinal cell rows; reproduction by monosporangia in cushionlike nema- 

 thecia. 



KEY TO SPECIES 



1. Branches generally more than 1.5 mm diam ... A. Durvillaei 



1. Upper branches generally less than 1.0 mm diam 2 



2. Closely di-polychotomously forked, reaching 7 cm in height; the 

 surface appearing dull when dry A. Svensonii 



2. Rather irregularly dichotomously forked, reaching 3 cm in 

 height ; the surface appearing slightly nitent when dry . . . 

 A. gigartinoides 



