norirnii. (iKNi'.iiA 



Tlio farli('>t kiunvn di'vcloiinifntal stajjos of '/'. 

 Lrpldilrsniitir consists of an tlliptical. rouiiil. or 

 irrojjiilar plasinoiliuin (?) which fills tlic hypcrtro- 

 phied host cell (fifc. !•)• Its protoplasm is honio- 

 pciK'ous, brownish, and slightly granular and not 

 enveloped by a distinct membrane With maturity 

 the protoplasm becomes more siramilar, and the en- 

 tire thallus segments into spores, which are at first 

 polygonal but later become oval and si)herical, 12- 

 1(5^. and develop smooth hyaline walls (fig. 5). 

 When mature they have a yellowish tint, and as the 

 sorus breaks open to the outside of the host it as- 

 sumes the structure and appearance of a cup-like 

 pustule tilled with pulvereseent spores (fig. 2). Ger- 

 mination of these sjiores has not been observed. 



P;itouillard's figures and description of the sorus. 

 spore formation, and the appearance of the pustules 

 suggest that T. Lcptodtumiae may possibly be a spe- 

 cies of Si/iichi/triiim of the .S. decipifiis type which 

 forms open Jjustules. His figures of a naked plas- 

 modial stage and comparatively thiek-walled spores, 

 however, militates against this view, but in dried 

 herb.arium material it is obviously difficult to deter- 

 mine tlie ])resence or absence of an enveloping mem- 

 brane. .Saceardo ('31 ) listed T. Lepiodc.im'iae among 

 the IMasmodioi)horaceae. but Cook ('33) excluded 

 it. Palm (see Palm and Burke. '33) collected mate- 

 rial of a species closely related, if not identical, to 

 Tremaiophli/ctis on an unnamed host in southern 

 Madagascar, and his statement that it is an "un- 

 doubted member of this family" carries the implica- 

 tion tli.it be believed Patouillard's genus might be 

 valid. Lnfortunatcly Palm has jjublislicd nothing 

 addition.il on this fungus, and the status of Tremaio- 

 phli/cti.i will remain doubtful until more is known 

 about its life cycle. 



In relation to these doubtful genera a discussion 

 of Pi/rrhosoriis .fuel may be logically presented at 

 this ))oint. although in so doing the author does not 

 imi)ly that it should be included in the Plasmodio- 

 ])horaceae as this family is now recognized. This 

 genus was created by ,Juel ('01) for an orange- 

 colored species. P. marinus, which he discovered in 

 a red alga, Ci/stoclonium piirpiirascens, in Sweden. 

 Since he found it only in dead branches .luel con- 

 cluded that it is a .saprophyte, but Winge ('13) be- 

 lieved that during some of the developmental stages 

 reported by ,Iuel the organism may be ]);irasitic. P.'/r- 

 rhosoru.s- mariniix has never since been observed, but 

 because it includes several ])lasmodi()i)hor.iceous-like 

 stages in its life cycb- it merits consideration in any 

 discussion of the Plasmodiophorales. .luel was uncer- 

 tain about its taxonomic position, relationship, and 

 phvlogeny but jiointed out and discussed the charac- 

 ters it lias in common with Jf'oronina, Iihi:nmi/xa, 

 Trtramjixa, Pnifomi/sa, and other genera of lower 

 organisms. He particularly stressed the similarity of 

 its tvjjc of sjiorogenesis to that of Trtrnmi/.ra. 



The life cycle of /'. marinus is as follows: In the 

 early developmental stages it consists of small globu- 

 lar thallus lying within the host cell (PI. 11-. fig. 8). 

 Such thalli may often be associated in pairs (fig. 9) 



or groups, and .luel aeeordiiigly considered it ))os- 

 sible tiiat they may l.-itcr co.ilisee and form a large 

 pl;ismodium. The iminucleate thallus grows in size 

 as its nucleus enlarges (tig. 10) and app.arently di- 

 vides. Mitoses in the iilasmodium have not been ob- 

 served, and .hiel was uncertain as to the manner of 

 origin of the multinucleate stages. A later stage is 

 shown in figure 1 1 of a plasmodium with four large 

 nuclei. The developing plasiiiodia a|)pareiitly Iiavc 

 the .ability to dissolve intervening cell w.ills ( fig. 1 1 ) 

 ■and m.iy eventually occujiy several cells. Although 

 they may be distinctly amoeboid in shajie with nu- 

 merous blunt, pscudopod-like extensions and vacu- 

 oles (fig. 12, 13) it is not certain from Juel's account 

 that they move about and migrate from cell to cell 

 as in Pla.smodiophora, etc. No evidence of schizog- 

 ony was observed by .luel. but \\'inge interjireted 

 some of the uninucleate stages as ))robable meronts. 

 The mature plasmodium is multinucleate, vacuo- 

 late, and usually irregular in shape (fig. 12-1 t), and 

 just before sporulating forms an enveloping mem- 

 brane like Sorolpidiiim. Plasmodia which are exten- 

 sively drawn out and occupy several host cells may 

 accordingly ap))car lobed, irregular and tubular (fig. 

 18) after the wall has formed. Following this stage 

 the i)roto])lasm divides into uninucleate segments. 

 In this process no distinct cleavage furrows have 

 been observed. The jilasmodium appears to become 

 highly vacuolate (fig. If) during this process, and 

 the cytoplasm accumulates around the nuclei and 

 forms stellate i)roto])lasmie islands which resemble 

 somewhat the sporonts of Teirami/ja. These seg- 

 ments soon become almost spherical or spindle- 

 shajjcd (fig. If), and .luel thought that the latter 

 type of cells arc formed in ])lasmodia which are 

 highly vacuolate and scarce in cytoplasm. In addi- 

 tion to these two kinds of segments, irregular elon- 

 gate, oval and smaller ones may be formed, appar- 

 ently as the result of unequal cleavage, which finally 

 degenerate. 



The si)herieal. 8 u. in diameter, and siiindle-shaped 

 segments are uninucleate, naked, and never develo)) 

 a distinct wall. They aggregate to form a definite 

 sorus (fig. 1.5) and each cell soon divides into oetads 

 of s))ores as in Octomi/.ra, which led .luel to call them 

 spore-mother cells. In this jirocess of spore forma- 

 tion the nuclei divide mitotically (fig. 21-2f) and 

 each mitosis is followed by cell division. Definite 

 chromosomes (2 to .5) are formed on a sharply-de- 

 fined sjiindle during mitosis, and there is no evidence 

 of "promitosis." according to .Juel's figures. Each of 

 the eight naked s])ores so(Ui becomes tr;ins formed di- 

 rectly into a zoospore without developing ;i thick wall 

 and becoming dormant. The mature zoospores are 

 small, ijyriform. 4..5X2..') /x, with a tajiering end, 

 laterally biHagellate and isocont (fig. 7). In addi- 

 tion they ))ossess ;i brilli;int or.ange-colorcd s))ot or 

 globule which rtsembles the eye sjiot of algae and 

 lies at the point of insertion of the tlagella. The zoo- 

 spores a))]jarently infect the host cells and develop 

 into the small thalli shown in figures 8 and 9. Cysto- 



