TETU.\MV\A 



Ho/.<-. M. K. IS!)!I. Hull. S(K-. Myoil. Fraiu-o lo: S7. 



Shibiitii, K. im:. .Iiihrl). wiss. Hot. :{7: (i«. 



S|ioschiu'w, N. N. 1!'07. nil- ril/.|iariisilcn <li"s 'rtcstrauclios. 



K.'riin. 

 Sollii. 1901. /.cit.schr. I'rtiiiiz.-nkr. II: J.'.S. 

 Sydiiw, H. 19.H. .\mi. Mvcol. .'.': .'9:1. 

 Wiiroiiin. .M. I.S(i(;. Mnn. .\c.iil. Sci. St. IVtirsliiirL' T sir. 10, 



no. (i: i:{. 



TETRAMYXA 



Gocbel, 1S«4', Floni G7 : 317 



(l-L.^TK 5. FIG. 1-26) 

 Molllardia Main- and Tison. 1911. Ann. Mypol. 9: :.?3G. 



Resting spores u.sii.illy in titrads hut often scpa- 

 ratinj; and lyinj; sinijly. or in iliads and triads ; vari- 

 ou.sly .sliapi'd. srivinj; rise to a sinu;li' nonflajiellate ( ?) 

 and anioelioid cell in aerniiiiation. Plasmodia usually 

 small, liocomini; |)arict.il in tlu- host cill at maturity 

 and clravinii into uninucleate spore-mother cells or 

 sporonts which usually divide twice to form tetrads 

 of resting spores. Zoosporangia and zoospores un- 

 known. 



Tctrami/da is the second ))lasniodioj)horaceous 

 genus to he recognized as such, and although it has 

 heen known for many years, our knowledge of its 

 critical develo|)niental stages is meager. It includes 

 at present two species and possihly a third one, which 

 is so imperfectly known that its inclusion in Teira- 

 mi/xa is very problematical. While this genus ap- 

 pears to be comparatively rare in occurence, it is 

 widely distributed and has been reported frotn Fin- 

 land. Germany, (ireat Britain. France, Morocco. 

 Ja))an. and California. L . .S. A. Further studies may 

 show it to be world wide in distribution. 



No zoosporangia or zoospores have been observed 

 in Tetramifxa, and the resting spores are reported to 

 give rise to amoeboid, nonflagellate cells. More care- 

 ful and intensive studies under optimum develop- 

 mental condition, however, may show that these cells 

 are biflagcllate and heterocont .ind that zoosporangia 

 also are developed. 



T. PARASITICA Chh-1i<-1. I.e. PI. 10. Hissliifrer, 1888. 

 Meddel. .Sue. Fauna et Flora Fenn. 14: .53. PI. 1-10. 

 Maire and Tison, 1911. .\nn. .Mycol. 9: 2-2H. PI. 10. 

 ThfC'iphorn Riipplae Setchell, 193i. Mycologia Hi: H:i. 

 PI. 18. Fig. 3, i. 



Resting spores spherical, 3. .5-7 /x. and angular. 

 with smooth hyaline walls, giving rise to nonflagel- 

 late (?) amoeboid cells upon germination. Plasmodia 

 usually several in a cell, small. 1.5— 30 /x. or almost 

 filling host cell. 



Parasitic in the stalks of Uiipjna ro.stfllata, Zaniii- 

 clidlia poli/cnrpa, and /. paluxtrm in Finland and 

 (iermany ( Hissingir and Cioeliels. I.e.) ; Ruppia sp. 

 and Z. palii.stri.s in Cireat Britain (Boyd. '97; 

 Schwartz. 11: Haddon. '22) ; li. rostrllata in France 

 (Maire and Tison. '10, '1 1). Potamocfelon panormi- 

 tanus in Morocco (Maire. '17: Maire and Werner, 

 '37). and Ruppia maritima var. roxtrata in C'jilifor- 



nia. U. S. A. (Setchell, I.e.). causing sni.ill or large, 

 ui» to 1.5 mm. in di.ini., greenish .-ind Later whitish — 

 brown g;ills on the st.ilks. peduneh-s. .ind lu.irgins of 

 the leaves. 



The galls (fig. 1 ) are primarily due to increased 

 cell multi})lication. The infected and adjacent cells 

 do not increase much in size, but are stimulated by 

 the parasite to divide ra))idly. This is ))artieularly 

 true of the infected cells, and by such means the me- 

 ronts or ))orti()ns of the ])lasinodiuni are j>assively 

 distributed to the res|)ective d.iughter cells (fig. !•). 

 This ap|)ears to be the ))rimary me.-ms of dispersal of 

 the parasite within the host tissue, although Cook be- 

 lieved that the amoebae are capable of migrating 

 from cell to cell. The relation between host and 

 l)athogcn is very intimate, according to ISIaire and 

 Tison. and no antagonism is exhibited. The cyto- 

 plasm of both often ap|)e.irs to be confluent, and it is 

 frequently impossible to determine the boundaries 

 between them. Although the nuclei of the host cells 

 may be enveloped by the jdasmodium (fig. 2). they 

 do not become enlarged and deformed or divide ami- 

 totically as in Triglochin palustre parasitized by T. 

 Triglochinis. When young, the infected cells contain 

 a fairly large amount of starch, but this usually dis- 

 ajjpears after the sporulation of the Jiarasite. The 

 nucleus remains intact for some time later, but even- 

 tually degenerates. 



Cook ('33) re])orted that this s])ecies had been col- 

 lected by Boyd and Haddon in Scotland and F'.ng- 

 land and that a diseased specimen of R. rosteUata in 

 the Father Reader Herbarium, University of Bristol, 

 had been collected as early as 1885 in Hampshire. 

 Maire and Tison (11) found T. parasitica in abun- 

 dance on R. rostellaia, which grew in close associa- 

 tion with Z. palu.siris var. pedicellata. The latter host 

 was not infected. Claire and Tison accordingly ex- 

 pressed doubt about Hissinger's report of the j)ara- 

 site's occurrence on L. polycarpa, because many au- 

 thors regard this species as only a form of Z. pa'its- 

 tris. 



T. TRIGLOCHINIS .Molliard. 1909. l?iill. -Soc. Hot. 

 France .56: i4. 

 Mntli„ril!fi Trii/lorhinis (.\I,ill.) Main- and Tison. 1911. 

 .Ann. .Mycol. 9: J.W. Pi. 1.', fig. +7 ()3; PI. 13. fig. G5-()7. 



Resting s])ores, zoos|)ores. and zoosjiorangia un- 

 known. Plasmodia small, usually numerous in a host 

 cell: undergoing niulti|)le division into several oval, 

 elongate, sickle-slia))ed uninucleate meronts which 

 grow in size, and during the two- to eight-nucleate 

 stage function in turn as schizonts. .\11 else unknown. 



Parasite on the stems, flowering stalks, stamens, 

 ovaries, but rarely on the leaves of Triqlochin paliis- 

 fra and 7'. maiifiniim in France (Molliard. Maire 

 .iiul Tison. I.e. ) and 7'. maritiinim in Kngland (Cook. 

 '33). causing small fusiform, ov.al .-ind irregular 

 galls. 



No resting spores have been observed in this s])e- 

 cies. so that its relationship to the other members 

 of the Plasmodiophoraceae is obscure. Because of 

 the lack of resting spores, Maire and Tison regarded 



