32 



PLASMODIOPHORALES 



sicae on crucifers and the malignant neoplasia in 

 animal cancer. 



Analogies have also been drawn between tlie club 

 root organism and the cellular inclusions formed in 

 vaccination against small pox. Gorini ('01) suc- 

 ceeded in producing a slow but marked proliferation 

 of the cornea epithelium in dogs by implanting in- 

 fected cabbage tissues and found that tlie intracellu- 

 lar effects were very similar to those caused in vac- 

 cination. Certain phases of P. Brassicae under these 

 conditions resembled the Ci/torcf/tes bodies associ- 

 ated with small pox. Pollacci ('12) pointed out some 

 of the striking resemblances between the early devel- 

 opmental stages of P. Brassicae and tlie Negri bodies 

 of rabies in dogs and believed that there might be a 

 connection between these two cellular structures. 



P. DIPLANTHERAE (Ferdinandsen and Winge) Cook, 

 193-'. Hong Kong Nat. Suppl. 1:34. 

 Oxtf'iifcUUella Diplantherne Ferdinandsen and Winge, 

 19U. I.e., pi. 45. Fig. 1-4. 



Resting spores globose, spherical, 4-4. .5 /j,. with 

 fairly thick, brown, smooth walls; germination un- 

 known. Zoospores and evanescent zoosporangia un- 

 known. Plasmodium filling host cell, 125-200^ in 

 diam. ; schizogony doubtful; cleaving directly into 

 uninucleate resting spores during sporogenesis. 



Parasitic in Diplanthera icrif/htii, St. Croix, West 

 Indies, causing large galls on tlie stems in the re- 

 gion of the internodes. 



This imperfectly known species was found in 1913 

 by Ostenfeld who turned over his material to Ferdi- 

 nandsen and Winge for further study. From this 

 scanty and poorly fixed material they created a new- 

 genus, Osienfeldiella, for the species at hand. Cook 

 subsequently examined their prepared slides and 

 concluded that the fungus is a species of Plasmodio- 

 phora. Because its plasmodia cleave directly into 

 resting spores which are not united in cystosori but 

 lie loose and separate in the host cell as in Plasmo- 

 diophora, there is no reason, on the basis of present- 

 day knowledge, for keeping this species in a separate 

 genus. Cook's disposition of it is accordingly fol- 

 lowed here. 



Ptasmodiophora Diplantherae attacks only the in- 

 ternodes and causes them to enlarge, so that the stem 

 has the appearance "of a string of pearls." as is 

 shown in figure 98. The parasite is restricted to the 

 inner cortex where it leads to marked enlargement of 

 the infected cells. Normal cells measure approxi- 

 mately 35 /i in diameter, while infected ones vary 

 from 12.5 to 200 (u. In the early stages of infection 

 the young liost cells apparently retain their ability 

 to divide, and it is not improbable that the young 

 parasites may be dispersed by division of the host 

 cell. The plasmodium seems to envelop the host nu- 

 cleus (fig. 99), and witli the start of the sporogonic 

 phase tlie nucleus begins to degenerate. The pres- 

 sure exerted by the enlarging cells causes tangential 

 stretcliing of tlie outer cortical elements, and in cases 

 of unilateral infection the central cylinder becomes 



laterallv displaced. Since the parasite is localized in 

 the inner cortex, infected stems can readily continue 

 to grow and elongate. 



Whether schizogony or any other division of the 

 parasite within the host occurs in this species is un- 

 certain. So far none has been observed. Ferdinand- 

 sen and Winge nevertheless concluded that the young 

 amoebae divide after each mitosis, because only uni- 

 nucleate stages are to be found in the meristematic 

 areas of the stem. 



P. HALOPHILAE Ferdinandsen and Winge, 1913. 

 Centralbl. Bakt. Parasitenk. II, 37: 167. Fig. a-c. 



Resting spores yellowish in mass, hyaline when 

 single, globose, 5 /a, with fairly thin smooth walls. 

 Plasmodia one to several in a cell, variable in size 

 and shape, subglobose. elongate, 30-60 /x long. All 

 else unknown. 



Parasitic in the petioles of Halophila oralis on the 

 island of Noesa Kembangan near the southern shore 

 of Java, causing conspicuous pea-shaped galls. 



The diagnosis of this species is based on a study 

 of dried material which Ostenfeld found in a collec- 

 tion of H. oralis in the Botanical Museum of Huana. 

 He believed that the hypertrophied petioles (fig. 

 103) were parasitized by a species of Plasmodi- 

 ophora but made no study of the organism. The dried 

 material was subsequently sent to Ferdinandsen and 

 Winge who diagnosed the parasite as a new species. 

 It has never since been collected, nor is anything 

 more known about its structure and development. 



The species which Feldman ('36) found on peti- 

 oles of Halophila BaiUonis in CJuadeloupe, West 

 Indies, may possibly be identical or closely related to 

 P. Halophilae. Feldman merely noted its occurrence 

 witliout describing or identifying the parasite. 



P. FICI-REPENTIS Andreuoci, 1926. Arch. But. 2: -26. 



Resting spores spherical. 1.5.5 /x. with thin, hyaline 

 walls; producing pyriform uniflagellate (?) zoo- 

 spores in germination ; flagellum 2.7 jx in length. 

 Thin-walled evanescent zoosporangia unknown. 

 Amoebae and young plasmodia from zoospores varia- 

 ble in shape and size. 6 X 24 ju,, aggregating and 

 fusing into larger plasmodia. which later cleave into 

 irregular segments and finally into spores; some- 

 times encysting to form hyaline, globular, 9.15-73 /x 

 cysts with granular and sculptured thick walls : cysts 

 producing plasmodia in germination. 



Parasitic on the large and small branches of Ficiis 

 repens in Italy, causing Avoody, brownish-gray, 

 globular, irregular and coral-like tumors up to 5 cm. 

 in diameter (fig. 102). 



This species differs from 7'. Brassicae ])rimarily 

 bv its smaller resting spores and the fact tiiat it at- 

 tacks aerial organs rather than the roots of its host. 

 It has been recorded but once, and Andreucci unfor- 

 tunately did not illustrate it. However, Cook ('33) 

 examined dried galls, which were unsuitable for cyto- 

 logical study, and described tliis species as a doubt- 

 ful member of the genus. 



