NO. 1 DAWSON : MARINE RED ALGAE OF PACIFIC MEXICO 3 



SYSTEM ATI C LIST 

 Goniotrichaceae 



A single species known in the Mexican flora. 

 Goniotrichum elegans (Chauvin) Zanardini 



Zanardini, 1847, p. 69; Smith, 1944, p. 161, pi. 35, figs. 1-2; Daw- 

 son, 1944, p. 251. Bangia elegans Chauvin, 1842, p. 32-34. Goniotrichum 

 alsidii (Zanard.) Howe, 1914, p. 75; Taylor, 1937, p. 215, pi. 28, figs. 

 1-4; Taylor, 1945, p. 132. 



Thalli epiphytic, filamentous, 0.5-5.0 mm. long or more, 12-30 (40) 

 fx. in diameter, simple or irregularly or pseudodichotomously branched ; 

 cells more or less quadrate, less than 10 /a in diameter, uniseriate, or 

 sometimes somewhat irregularly multiseriate below, enclosed in a thick, 

 continuous, hyaline wall, with radiate chromatophores ; reproduction by 

 monospores liberated by dissolution of the thallus membrane. 



Type: Holotype not designated. Syntypes collected by Chauvin, 

 Aug.-Sept. 1834, were distributed in Chauvin's Algues de la Normandie, 

 fasc. 7 no. 159. A copy is in HAHF. 



Type locality: Epiphytic on various algae, Arromanches, Calva- 

 dos, France. 



Mexican distribution: Pacific Baja Calif. — with Acrochaetium 

 davisiij Isla Guadalupe, Aug. ; on Zostera^ Ensenada, Oct. Gulf of Calif. 

 — epiphytic on various algae, throughout. Sinaloa — on Gelidium, Ma- 

 zatlan, Dec. Nayarit — on Bryothamnion dredged from 5-9 m., Isla 

 Maria Magdalena, May. 



Erythrotrichlaceae 



Key to the Mexican Genera and Species 



1. Mature thallus consisting mainly of erect, free filaments 



Erythrotrichia 4 



1. Mature thallus discoid, with some of the cells of the central part 

 projecting upward as short filaments Erythropeltis discigera 



1. Mature thallus discoid or of prostrate filaments, without erect, 



free filaments Erythrocladia 2 



2. Thalli epizoic, of irregularly branched, prostrate filaments 



forming a network E. ectozoica 



2. Thalli epiphytic, discoid 3 



3. Margins subentire, with many bifurcate cells .... 

 E. subintegra 



