60 



PLASMODIOPHORALES 



become invested with a wall (fig. 31), and mature 

 into resting spores. These spores usually remain at- 

 tached to each other and form cystosori of variable 

 sizes and shapes (fig. 28-40) in accordance usually 

 with the size of the plasmodium and tlie shape of the 

 host cell. 



L. JUNCI (Schwartz) Maire and Tison, I.e. 



Sornsphuera Jiiiici Schwartz, 1910. Ann. Bot. 24: 513. 



PI. 10. 

 S. (/raminh Schwartz, 1911. Ibid. 25: 791. PI. (il. 

 L. graminh (Schwartz) Winge, 1913. Ark. f. Bot. \-2, 



no. 9: 15. 

 L. rridicdlii Maire and Tison, I.e.; 1911. Ann. Mycol. 9: 



333. PI. 11, fip. 34-38. 

 L. Bellidis Schwartz, 1914. Ann. Bot. 38: 333. PI. 13, fig. 



7-8. 

 L. Menthae Schwartz, I.e. PI. 13, fig. 1-6. 

 L. AlisnuiUs Schwartz, I.e., p. 333. 



Resting spores rarely in tetrads, sometimes end to 

 end in a linear series ; more often in irregular masses, 

 solid or hollow, flat, globose or ellipsoidal, cylindri- 

 cal and elongate cystosori. Resting spores spherical 

 oval, angular and polyhedral when compressed to- 

 gether, 4-7 /i in diameter, with relatively thin hya- 

 line smooth walls; apparently giving rise to zoo- 

 spores which infect the host cell. Plasmodium partly 

 or completely filling the host cell ; segmenting into 

 either zoosporangia or one or more masses of rest- 

 ing spores, schizogony questionable or reduced. Zoo- 

 sporangia oval, subglobose, spherical, angular and 

 polyhedral, 15-20/x, in diameter, with thin hyaline 

 smooth walls; method of dehiscence unknown. Zoo- 

 spores from sporangia 4 to 8 in number, pyriform, 



3. 5X^-5 jn. 



Parasitic in the root hairs and roots of Junciis arti- 

 ciilatus, J. obiusiflorus, J. biifoniiis, J. lamprocar- 

 piis, Poa annua, Bellis perennis, Mentha piilegium, 

 Alisma Plantago, CallHriche stagiialis, Votomgeion 

 natans, Polyc/onum H i/dropiper. Iris pseudocorus, 

 Ranunculus circinatus, R. aquatilis, Plantago ma- 

 jor, Cerastium vidgatum, Veronica Beccahunga, 

 and Chri/santhemum leucanthemum in England 

 (Schwartz, '10, 'II, "14; Cook, '26, '27, '28. '33) ; 

 Callitriche stagnalis and Poa annua in France 

 (Maire and Tison, I.e., 'lib); Alisma Plantago in 

 New York, U. S. A. (Karling, '34). 



Cook ('26) made extensive cross inoculation ex- 

 periments involving 16.5 individuals of different spe- 

 cies, 151 of which became infected with L. Junci 

 after four months. These plants included the hosts 

 of Schwartz's L. graminis, L. Bellidis, L. Menthae, 

 and L. Alismantis, and since Cook found no essen- 

 tial differences between these Ligniera species and 

 L. Junci, he concluded that they are identical. The 

 species which he found in Callitriche stagnalis was 

 likewise capable of infecting the same hosts ; and for 

 this reason he ('33) later concluded that L. radicalis 

 described by Maire and Tison in C. stagnalis in 

 France is also identical to L. Junci. The resting 

 spores of L. radicalis, however, are only 4- .5 /x in 

 diameter, while those of L. Junci range from .5 to 

 7 /x. This difference is not very great and may not 



PLATE 1 1 

 Liffniera 



Fig. 1. Zoospore highly magnified (Z/. .Tunc!: Cook, '38). 

 Fig. 3a. Zoospore outside of root hair; 3b, after entering 

 host cell (Cook, "36). 



Fig. 3, 4. Developmental stages of amoebae and young 

 Plasmodium (L. (/ramini.i; Schwartz, '11). 



Fig. 5. Young thallus with five engulfed alga! cells (L. 

 radicalis ; Maire and Tison, '11). 



Fig. 6. Two amoebae approaching a central host nucleus 

 (L. fframinin; Schwartz, "11). 



Fig. 7. Amoebae clustered around host nucleus {L. (/ra- 

 mini.'i Schwartz, I.e.). 



Fig. 8. Young amoeboid plasmodium (L. (/rfiminis; 

 Schwartz, I.e.). 



Fig. 9. Young plasmodium in root hair; nuclei with large 

 karyosome and abundant chromatin {L. .Junci; Cook, '3fi). 

 Fig. 10. Possibly schizogony of plasmodium {L. radi- 

 calis; Maire and Tison, I.e.). 



Fig. 11. "Promitosis" of vegetative nuclei (L. (/rdminis; 

 Schwartz, I.e.). 



Fig. 13. Single large plasmodium in a host cell. Nuclei 

 entering akaryote stage (L. fframini.i: Schwartz, I.e.). 



Fig. 13. Akaryote stage; nuclei appear as clear spaces 

 {L. graminis; Schwartz, I.e.). 



Fig. 14. Akaryote state; cytoplasm with numerous chro- 

 matic granules ; host nucleus densely chromatic in base of 

 cell (L. radicalis; Maire and Tison, I.e.). 



Fig. 15-18. Successive stages of extrusion of chromatin 

 from the nucleus (L. .fund: Cook, "33). 



Fig. 19. Prophase of heterotypic division (?) in a recon- 

 structed nucleus {L. .Junci: Cook, "38). 



Fig. 30. Cleavage of plasmodium into zoosporangia; the 

 two large mitotic figures in upper left segments are equa- 

 torial plate stages of the first heterotypic division (?); 

 the remainder relate to homeotypic division (?) (L. .Junci; 

 Cook, "36). 



Fig. 31. Cleavage into zoospores {L. .Junci; Cook, "38). 

 Fig. -23. Second mitoses prior to resting spore formation 

 {L. radicalis; Maire and Tison, I.e.). May possibly relate to 

 sporangia and zoospore development like in figure 30. 

 Fig. 33. Zoosporangia {L. Junci: Cook, '38). 

 Fig. 34. Empty zoosporangia {L. .Junci; Cook, '38). 

 Fig. 35. Plasmodium in swollen root hair tip {L. pilo- 

 rutn : Fron and Gaillat, I.e.). 



Fig. 37. Cluster of empty resting spores in swollen root 

 hair tip (L. graminis: Schwartz, I.e.). 



Fig. 38, 39. Small groups of resting spores (L. Minthae; 

 Schwartz, "14). 



Fig. 30, 31. Types of resting spore clusters (i. graminis; 

 Schwartz, '11). 



Fig. 33. Single resting spore {L. .Junci: Cook, "38). 

 Fig. 33. Resting spore ball filling host cell {L. Jsoetes; 

 Palm, '18). 



Fig. 34. Cross section of a similar hollow resting spore 

 ball {L. Isoetes: Palm, I.e.). 



Fig. 35. Loose chain of resting spores (L. Isoetes: Palm, 

 I.e.). 



Fig. 3(i. Longitudinal section of hollow cylindrical rest- 

 ing spore cluster (L. radicalis: Maire and Tison, I.e.). 



Fig. 37. Cluster of resting spores with host nucleus inside 

 (L. radicalis: Maire and Tison, I.e.). 



Fig. 38. Resting spore clusters of L. piloruni in swollen 

 base and tip of root hair (Fron and Gaillat, I.e.). 



Fig. 39, 40. Types of resting spore clusters (L. verru- 

 cosa; Maire and Tison, I.e.). 



