Coelodiscus endophytus, a chlorophycean alga from the Lake of Ohrid, Jugoslavia

Coelodiscus endophytus (Möbius) v. d. Hoek nov. comb. — Bulbocoleon endophytum Möbius, 1891, p. 1292—1293. — Endoderma endophytum (Möbius) Huber, 1892, p. 325— 326. — Ectochaete endophytum (Möbius) Wille, 1909, p. 79; Heering, 1914, p. 98; Printz, 1964, p. 204. — Endoderma jadinianum Huber, 1892, p. 322—326. Thallus tubular or saccate, irregularly lobed or plicate, eventually opening and splitting, growing attached to Cladophora glomerata by coalescent endophytic branched filaments, up to 1 cm long and 0.5 cm broad. On cross-section, the wall of the hollow thallus consists of two to three layers; one or two innermost layers of large, rounded or slightly elongate, mostly colourless cells, 30—60 µ in diam., and one, sometimes two, outer layers of smaller, chloroplast-bearing cells, 13—30 µ in diam., which very rarely are provided on their outer face with a colourless hair, 1.5—2.5 µ in diam. The outermost cells can be transformed into flask-shaped zooidangia which produce zooids ca 10—15 µ in diam. and which release these zooids through apical pores. The chloroplasts are parietal and are provided with 2—7 bilenticular pyrenoids 2.5—5 µ in diam. and bearing mostly 2 bowl-shaped starch-bodies. The chloroplasts of the endophytic filaments generally contain 1—2 larger pyrenoids 3.5—6.5 µ in diam.