THE SIMPLE HOLOCARPIC BIFLAGELLATE PHYCOMYCETES 



and sporangiosori of Cook's fungus may possibly 

 belong to either W. glomerata or W. aggregata, or 

 a new species. According to Fischer ('92) W. poly- 

 ci/stis is limited to species of Saprolegnia and will 

 not infect Achlya, but subsequent workers have not 

 confirmed his observations. So far no intensive cross 

 inoculation experiments have been made. The valid- 

 ity of Peterson's forma scalariformis is open to seri- 

 ous question. 



As noted elsewhere, Fischer, Zopf, Cook and 

 Nicholson described the mature vegetative thallus 

 as a plasmodium, but they did not prove conclusively 

 whether it arises from a single infection or by fusion 

 of several amoebae within the host cell. Minden be- 

 lieved that in cases of multiple infection fusion of 

 several protoplasts is not an improbable occurrence. 

 According to Fischer the thallus may exhibit many 

 of the characteristics of a plasmodium, undergoing 

 amoeboid changes in shape which are accompanied 

 by slow and weak wave-like streaming of its dense 

 protoplasm. As to its mode of feeding, Zopf main- 

 tained that it engulfs the protoplasm of its host di- 

 rectly. Cook and Nicholson reported that it feeds on 

 glycogen and the oil globules of its host, because 

 they were able to demonstrate by microchemical 

 tests the presence of the same substances in both the 

 host and parasite. They, furthermore, maintained 

 that the mature plasmodium or young sorus becomes 

 surrounded by a cellulose wall as it segments into 

 sporangia and spore rudiments ; yet none of their 

 figures show the presence of such a wall. 



W. GLOMERATA (Cornu) Fischer, 1892. Rabenhorst's 

 Kryptog. Fl. I, 4:64. 

 Chi/trkiium glomeratum Cornu, I.e., p. 187, pi. 7, figs. 

 20-2-2. 



* Zoosporangia occasionally single, more often in 

 small groups or loose aggregates which measure 

 50-96 fi X 70-300 /* ; individual zoosporangia hya- 

 line, smooth, oval or spherical, 10-33 /x, with a single 

 broad flask-shaped exit tube which may or may not 

 project beyond the surface of the host. Zoospores 

 hyaline, oval, 2-2.6 ju, somewhat kidney-shaped or 

 ellipsoid, 2.4 X 3.6 ft., with numerous small gran- 

 ules ; position and relative lengths of flagella un- 

 known. Resting spores in groups like the zoospo- 

 rangia, hyaline, spherical or ellipsoid, 12-24 /*, with 

 a granular content, thin endospore, and thick exo- 

 spore which has a net-like sculptured surface simi- 

 lar to that of Tilletia Iritici; functioning as a zoo- 

 sporangium in germinating and producing numer- 

 ous zoospores. 



Parasitic in J'aucheria sessilis, J', terrestris and 

 Vaucheria sp., in France (Cornu, I.e.), Germany 

 (Zopf, '94), Hungary (Scherffel, '25), Bulgaria 

 (Valkanov, '31) and Japan (Tokunaga, '33), caus- 

 ing septation but no hypertrophy of the infected 

 host filaments. 



W. AGGREGATA Zopf, 1894. Physiol. Morph. Nied. 

 Organismen 4:(i0. 



Zoosporangia, 10 to 20 in number, grouped in 

 round grape-like clusters or sori, hyaline, smooth 



and spherical with a tubular cylindrical exit tube. 

 Zoospores and resting spores unknown. 



Parasitic in Mougeotia sp., in Germany. 



This species has the same type of development as 

 TV. glomerata, according to Zopf, but differs pri- 

 marily by the arrangement of the zoosporangia >n 

 the sorus and the presence of non-inflated exit tubes. 

 Zopf also observed a similar JT'oron/tta-like organ- 

 ism in the mycelium of I'ilobolus, but he did not iden- 

 tify it. 



DOUBTFUL SPECIES 



W. ELEGANS (Perroncito) Fischer, I.e., p. 66. 



Chytridmrn elegans Perroncito, 1888. Centralbl. Bakt. 

 Parasitk. 4: 295. 



Sporangesori single, spherical to star-shaped, 

 6-1 10 fj., rosy red in color and made up of 8-20 spo- 

 rangia. Zoosporangia smooth, spherical, 20-30 (t., 

 egg-shaped or pyriform with several 4-5 /j, X 

 5-100/j. cylindrical exit tubes which bore through 

 the cuticle of the host. Zoospores oval, somewhat 

 elongated, 2-4 jx. X 4-5 fi, with two long flagella and 

 numerous minute red granules ; position and relative 

 lengths of flagella unknown. Cystosori and resting 

 spores unknown. 



Parasitic in Philodina rosetta in Italy. 



plate 2 



Woronina glomerata 



Fig. 1. Septate filament of Vaucheria terrestris with 

 six cystosori. Zopf, '94. 



Fig. 2. Septate portion of a V. sessilis filament with 

 numerous amoebae, some united by fine protoplasmic 

 strands and containing chlorophyll granules. Zopf, I.e. 



Fig. 3. Same, five hours later. Amoebae have separated, 

 begun to retract their pseudopods, and are rounding up. 

 Extraneous chlorophyll granules have been extruded. 

 Zopf, I.e. 



Fig. 4. Two amoebae with extraneous material in food 

 vacuoles, Scherffel, '25. 



Fig. 5. Sporangiosorus of four sporangia, one of which 

 has emitted its zoospores. Extruded waste material lying 

 nearby. Scherffel, I.e. 



Fig. 6. Large sporangiosorus. Zopf, I.e. 



Fig. 7. Two large sporangiosori. Tokunaga, '33. 



Fig. 8. Single sporangium undergoing cleavage. Zopf, 

 I.e. 



Fig. 9. Zoospores emerging from zoosporangia. Note 

 inflated exit tubes. Zopf, I.e. 



Fig. 10. Cystosorus of loosely united and separate rest- 

 ing spores. Zopf, I.e. 



Fig. 11. Enlarged view of resting spore with sculptured 

 exospore. Zopf, I.e. 



Fig. 12. Early germination stage. Zopf, I.e. 



Fig. 13. Group of germinated resting spores with long 

 exit tubes. In two of the pairs the superficial zoospo- 

 rangia or indospores have fused to form a common 

 vesicle. Zopf, I.e. 



Fig. 14. Resting spore of II'. asterina. Tokunaga, I.e. 



