Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 68. (Budapest 1976)
P. Komáromy, Zs.: Studies on terrestrial Chlorhormidium (Kütz.) Fott species (Ulotrichales)
Chlorhormidium nüens (MENEGH.) KOM. comb. n. Bas.: Hormidium nitens MENECH. em. KLEBS. — S y n. : Hormidium pseudostichococcus HEERING. Stichococcus bacillaris GAY. In some of the samples the filaments appear which as far as the mode of growth is concerned much resemble Hormidium nitens as described by KLEBS 1896. In the vegetative stage it forms a silky, somewhat wrinkled film on the surface of the enrichment and liquid cultures. The mass of the threads consist of more or less dissociated filaments, with rounded end-cells, 4,5-5 jjun thick. The length of the cells ranged from 5 mu, to 15 \im. Each cell include a distinct pyrenoid with starch adhering to the parietal chloroplast. This phenomenon has always occured in vegetative stage. I was not able to collect anywhere the resting form of this species. The reproduction by fragmentation was observed under culture conditions and also in nature. It was like Chlorhormidium flaccidum (KÜTZ.) FOTT. Earlier this species was incompletely known because it was very rarely encountered in nature. Chlorhormidium flaccidum (KÜTZ.) FOTT Syn.: Ulothrix subtilis GISTL. — Ulothrix subtilis var. variabilis BRISTOL — Ulothrix variabilis MOOR &KARRER — Ulothrix flaccida (KÜTZ.) A. BR. — Ulothrix flaccida var. antliaria (KÜTZ.) HANSG. — Hormiscia flaccida (KÜTZ.) LAGERH. —Hormiscia flaccida var. minorHANSG. —Hormidium flaccidum f. typ. HEERING — Hormidium mucosum B. PETERSEN — Chlorhormidium flaccidum var. flaccidum FAROOQUI — Chlorhormidium flaccidum var. nitens FAROOQUI. The species agrees with HEERING'S forma typica, in the vegetative stage. In enrichment cultures the threads are 5,5-7 jam thick and the cells are 5-15 u.m long. However, the filaments under various culture conditions are the same: diameter 6,3-7 Ltm, cell's length 5,5-24 Lun. A specific character of the species is that in liquid media the threads in different physiological states differentiate according to their weight (KOMÁROMY 1974). In resting stage the filaments have thick vertical cell-walls and this species pass unfavorable conditions in this state. I collected a mass of thick-walled filaments on a big rock covered with clay in February. Within a short time from some filaments by rupturing these thick-walled cells are liberated very short filaments. Reproduction by fragmentation is frequent, occurring especially in early spring and autumn. It occurs at the points where the filaments bend so that the fragmenting threads often present a characteristic zigzag appearence. I have not seen a zoospore formation. I think that reproduction by zoospores rarely occurs be it in nature or in cultures. Though we may observe simple cell division fairly often. We may also see the disorganization of the cells under unfavorable conditions. In this stage the ehloroplasts are disintegrated to rounded pieces and some vacuoles and granules will form in the cytoplasm. Sometimes these cells resume activity at other times they are destroyed (Figs. 1 — 5).
