298 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 12 



BRYOGLADIA Schmitz, 1897 



Plants with a creeping, matted base, bearing erect filaments which are 

 alternately branched, ecorticate, with 6 to 16 pericentral cells; lateral 

 branches spirally placed, short and stiff, ultimately commonly recurved; 

 tetrasporangia single in the segments, inserted along the outer side of the 

 branchlets; pericarps urn shaped, stalked, on the lateral branchlets. 



Bryocladia Dictyurus (J. Agardh) n. comb. 

 Plate 98, Fig 2 



Plants tufted, 1.5-3.0, seldom to 5.0 cm tall, dull blackish purple, the 

 base creeping and attached by haptera, the erect axes rather crowded, 

 simple or occasionally divided, 150 /j, to over 200 /j. diam., the segments 

 about 90 /x long, rather closely beset with divaricate branches 1-2 mm 

 long, 30-40 fjL diam., which branch alternately 3-4 times, the terminal 

 divisions tapering sharply and ending in acute, spreading, or recurved tips. 



Agardh, J. G. 1847, p. 16; Harvey 1853, p. 53 (both as Polysiphonia 

 Dictyurus) . Not Polysiphonia Dictyurus Hollenberg 1944, p. 479. 



The type locality of this species is Vera Cruz on the western coast of 

 Mexico, a place now difficult exactly to locate, where it was collected by 

 Liebmann. The present specimens seem considerably coarser than the type 

 material at Lund which the writer has seen, but it has probably been 

 browsed over and many coarse cut-off stems remain, the new growth being 

 dense and not reaching typical height. The plants did not adhere to paper 

 at all. These plants show the same general structure as B. thyrsigera (J. 

 Agardh) Schmitz. In that species the main axes are more percurrent, the 

 determinate branchlets more elongate. The habit of B. Dictyurus is more 

 compact and the short branches near the tip produce a round-topped ap- 

 pearance to each ; they spread more, are stouter and more rigid than in B. 

 thyrsigera. They are as distinct from the main axis as in the Caribbean 

 plant, or even more; and, since this is the chief distinguishing feature of 

 the genus, it seems well to transfer this species to it. 



Mexico : Guerrero, on coarser algae on the rocks near high tide line, 

 Ba. Petatlan, nos. 34-574, 34-517, 2 Mar. 1934. 



POLYSIPHONIA Greville, 1824i9o 



Plants erect, or with a rhizomatous base, usually abundantly branched, 

 the branches cylindrical, similar to the axis, growing from a definite 

 apical cell; structurally composed of a central cell row surrounded by 



190 Identifications in the genus Polysiphonia, and notes on the various species, 

 are included by the kindness of Professor G. J. Hollenberg. 



