NO. 1 TAYLOR: PACIFIC MARINE ALGAE 99 



3. Plants with decumbent to assurgent fronds, 5-10 cm long, usually 

 coherent, usually uncalcified; apical margin rolled upwardly, 6 

 layered in the outer part, with primary hair lines on the lower 

 face ; upper cortical cells 20-30 ju, deep, lower cortical cells 30-40 

 fi deep; basal region of the blades 12-20-stratose and 400-500 /* 

 thick; sori in each interpilary zone forming 2-3 bands, or scat- 

 tered or fusing over 2-3 zones P, concrescens 



3. Plants with erect free fronds 5-40 cm tall, usually lightly calci- 

 fied, chiefly on the lower surface; apical margin rolled down- 

 wardly, 3-6-layered in the outer part, with primary hair rows 

 on the upper face; upper and lower cortical cells usually 20-30 

 fi deep; basal region of the blade 10-18-stratose, 250-500 /a thick; 

 sori in each interpilary zone forming a number of bands or scat- 

 tered, but not fusing over several zones .... P. Durvillaei 



Padina caulescens Thivy n. sp."-^ 



Plant to 16 cm tall, 14 cm broad, repeatedly split, with flabellate seg- 

 ments 0.5-1.5 cm wide; stipe conspicuous, to 1.5 mm thick for 1-2 cm above 

 the base, above subdivided, 6-8 cm long, flat and stupose; blades lightly 

 or not calcified, with piliferous zones 1 mm apart, the hair lines of the 

 lower surface when present opposed to those of the upper surface; thick- 

 ness at the involute apex of two cell layers and about 45 /t, in the lower 

 central portion of the blades to 220-250 /x and 9-12 cell layers; upper 



72a Padina caulescens Thivy n. sp. (ex manuscripto inedit.) — Plantae dioeciae 

 altitudine usque ad 16 cm, flabellatim divisae, latitudine 14 cm, segmentis flabelli- 

 formibus, inferioribus deorsum in ramos stipitis flabelliformibus, inferioribus deor- 

 sum in ramos stipitis tenues attenuatis; stipite primario valido, 1.5 mm crasso, 1-2 

 cm alto, subcylindrico, ramos 0.5 mm crassos stuposos emittiente; parte frondis a 

 rhizoideis inclusa laminiformi, i. e., typice frondosa; lineis piliferis inter se ca. 

 1 mm distantibus in frondis parte juvenili sed ca. 3 mm in parte vetustiore, pro 

 parte amphigenis, oppositis, pro parte solum visis in aspectu superiore; fronde in 

 media parte et stipite 9-12-stratosis, 200-250 \i crassis, utrinque absque cake, vel 

 in pagina inferiore continue sed tenuiter et in pagina superiore discontinue et dis- 

 perse calciferis; cellulis superioribus corticis 20-25 |.t diam., isodiametientibus vel 

 dupio vel triplo longioribus quam crassioribus, duplo brevioribus quam cellulis 

 subcorticalibus vel eas aequantibus; cellulis corticalibus inferioribus diametro 

 superiores aequantibus, 2- vel 4-plo longioribus, longitudine subcorticales in regione 

 1 cm infra partem involutam aequantibus, in regione inferiore, transverse divisis, 

 duplo vel triplo longioribus et duplo brevioribus quam subcorticalibus, vel eas 

 aequantibus; in sectione transversali cellulis stratorum adjacentium oppositis; soris 

 zonatis, zonis antheridialibus in planta mascula et oogonialibus in planta feminea 

 consecutivis in pagina inferiore; soris antheridialibus plus minusve dispersis cum 

 cellulis basalibus 12-25 \x longis, 12-18 |.i altis, duplo vel quadruple brevioribus 

 quam cellulis corticalibus; soris oogonialibus 0.25 mm latis, medianis, zonam unam 

 vel duas imperfectas formantibus. Planta typica in loco dicto. I. Maria Magda- 

 lena, Las Tres Marias, Mexico, legit W. R. Taylor no. 39-669, 9 May 1939. 



