LAOENIDIACBAE 



79 



Pitkophora sp.. Stigeoclonium tenue, Ulothris 

 sonata, Oedogonium sp.. Spirogyra sp., S. crtuta, 

 Mougeotia sp., and Hydrodictyon reticulatum with- 

 out success. These results oast doubt on Schultz- 

 Danaig's report of the occurrence of this species in 

 Cotmarium. He based his claim on the presence of 

 an irregular, lobed, sac-like thallus with an exit tube 

 which is rarely branched, and the presence in the 

 same culture of pollen grains infested with /.. /','/<7- 

 macum. It is not improbable that his fungus relates 

 to dwarf thalli of MysOcytium or another species of 

 Lagenidiutn. Zopf's report that the zoospores are 

 li; to I8/1 long is obviously incorrect. The present 

 writer has observed their formation and activity nu- 

 merous times and found them to he approximately 



5 X8 ft in size and bean-shaped with a ventral 

 groove. 



Thalli of this species may look strikingly like 

 those of Olpidium, and unless zoospore emergence is 

 observed they may readily be mistaken for this chy- 

 trid. Fischer believed that the intramatrical resting 

 spores of R. pollinis noted by Cornu ('72. p. 121) 

 relate to /.. pygmaeum also. Atkinson (09) believed 

 that the zoospores of L. pygmaeum species are di- 

 planetic — the emergence of the incompletely de- 

 veloped zoospore segments representing the initial 

 motile stage. 



Whether Scrbinow's ('99) Olpidium ramosum 

 relates to this species or belongs at all in the genus 

 Lagenidium is very doubtful. Mention is neverthe- 

 less made of it here because it occurs in pollen grains 

 of l'inus sylvrstr'is in Russia and is reported to form 

 oospores. However, the zoospores are fully formed 

 in the ^oosporangium, possess a single posterior 

 flagellum, and swim directly away after emerging 

 from the branched exit tubes. In sexual reproduc- 

 tion two thalli, apparently of unequal size, fuse 

 within pollen grains and become invested with a 

 thick wall. This type of fusion is suggestive of that 

 which occurs in Olpidiopsis, but the presence of 

 posteriorly uniflagellate zoospores excludes O. 

 ramosum from this genus as well as from Lageni- 

 dium. 



L. GRACILE Zopf, I.e., p. 158. Cook, 1932, New Pbytol. 

 SI: 140. Figs. 32-38. [936. Arch. Protistk. 8i>: hk. pi. 

 3, fijrs. _>ii 32. 



Thallus very similar to that of L. entophytum 

 but usually narrower, 4.5 /x, and less irregularly 

 branched, sometimes penetrating adjacent host 



Cells. Sporangia less irregular, tubular, cylindrical. 

 1.5 /' in diameter, and occasionally almost spherical 

 with a narrow uneonstricted exit tube of variable 

 Length, which may become inflated before passing 

 through the zygospore and gametangium wall of the 



host; extending for varying distances beyond. Zoo- 

 spores bean-shaped, 4 X 7.5 ft., formed in an extra 

 matrical vesicle (?); vesicular membrane doubtful. 

 Oogonia intercalary, rarely terminal, oval, globular, 



paunchy; antheridia lacking. Oospores few or nu- 

 merous, parthenogenetic, formed as in /.. entophy- 

 tum, spherical, 13—14/1, with a thick smooth wall; 

 germination unknown. 



Parasitic in the zygospores of Spirogyra sp. in 



Germany (Zopf, I.e.) ; S. grevilleana in Belgium (de 



Wildeman. '!»">). and Spirogyra sp. in England 



( Cook, I.e.). 



From the above description, the validity of this 

 species seems very questionable. The slight differ 

 enees in diameter, irregularity of branching, length 

 and diameter of exit tubes, etc., noted by Zopf and 

 Subsequent workers are not Sufficient to distinguish 



it sharply from /,. entophytum, and inasmuch as 

 both are parthenogenic and inhabit the zygospores 

 of Spirogyra, the author is strongly of the opinion 

 that they are identical. Zopf's claim that the oospores 

 differ by being smooth and not bright golden in 

 color does not seem particularly significant, since 

 such oospores have been reported in L. entophytum 

 also. 



L. ZOPFII <le Wildeman, 1891. Bull. Soc. Beige Micro. 

 Hi: 139. Petersen, 1909. Bot. Tidskr. 9: 401. Fig. XVIb. 



Thallus irregular, branched, septate; consisting 

 of elongate, cylindrical and vesicular segments, and 

 extending through 3-4 host cells. Sporangia and 

 zoospores unknown. Oogonia vesicular and paunchy ; 

 oospores 14 ft in diameter with an irregular warty 

 wall; content refractive, large globule lacking; 

 germination unknown. 



Parasitic in Oedogonium sp. in Belgium (de 

 Wildeman, I.e.) and Jutland (Petersen. '09, '10). 



This species has been reported but twice, and 

 Petersen's single figure of it is the only one extant, 

 as far as the writer is aware. De Wildeman ('93, 

 p. 11) and Minden (11) believed it may possi- 

 bly be identical to L. syncytiorum described be- 

 low, and Cook ('35) listed it as a synonym of the 

 latter species. However, if the two are identical, L. 

 syncytiorum should be the synonym, since L. zopfii 

 has priority. While the author is inclined to agree 

 with the view at present that they may be identical, 

 both species are too incompletely known to warrant 

 definite conclusions. For this reason they are here- 

 with treated as distinct species for the time being. 

 According to de Wildeman, the thallus is similar to 

 that of /.. rabenhorstii, but Petersen described it as 

 narrower and less branched. The oospores, on the 

 other hand, resemble those of L. entophytum. 



L. SYNCYTIORUM Klebahn, 1895. Jahrb. Wiss. Bot. 

 J I: .'(i:S. PI. 3, tigs. 22-U. 



Thallus at first straight, 3-5 /'. irregular, curved. 



beady, filamentous and continuous; later becoming 

 septate and more irregular with numerous protuber- 

 ances; extending through several incompletely 

 divided host (alls. Thallus segments and sporangia 



spherical, oval, ellipsoidal, N 10/' in diameter, 

 spindle shaped, elongate, curved and somewhat ir- 

 regular with a single short exit tube which does not 

 project very far beyond the host cell. Zoospores. 

 OOgonia, antheridia and oospores unknown. 



Parasitic in Oedogonium boscii in Germany ( Kle- 

 lialin. I.e. i and Oedogonium sp. in Belgium I' 

 Wildeman, '96). 



