158 



Othek Species i?ei,<)N<;in<; t<> this (tkoii' 



The following;' spec-it's also Itelonii' to this oroup uiui u])pear to })e 

 distiiK't from the foreoojng, l)ut our kuowledoe of their cultural char- 

 aeters is more or less imperfect: 



(1) Ps. jugla/idis Fierce. Parasitic on the young- mits. leaves, and 

 stems of '/f/(/h(7is rxjia in California. The cause of an economicjilly 

 serious disease in walnuts. Resembles ]\. vainp&'itrh. Pierce does 

 not mention having* attempted to inoculate his organism into cruciferous 

 plants, hut the writer has tried the reverse of this without success, 

 viz, inoculations of Px. cainpei^trU and Pi<. 'pluixioli into 3^oung- rapidly 

 growing shoots of the walnut {J, regia). 



(:2) Ps. vmeularuni (Cobb). Parasitic on sugar cane in Australia 

 and elsewhere. The vascular bundles are filled with a yellow slime, 

 the canes are dwarfed, and the sugar content is reduced. 



(3) T^v. diantld (Arthur and Bolley). Isolated from carnations 

 (Dianthus spp.), and supposed to ))e the cause of a spot disease. Com- 

 mon on the surface of carnation leaves, but now believed to be purely 

 saprophytic. 



(i) Px. amarantl \\. sp. Occurs on species of Amarantus (weeds in 

 tields) in the Eastern United States, filling and browning the vascular 

 bundles and hollowing out the tissues in their vicinity into closed cavi- 

 ties filled with this organism. The plants which are attacked are 

 stunted, droop, and dry up without any visible cause. The organism 

 is a short rod and when grown on culture media has more orange in 

 its pigment than any others here described. On the whole, it seems 

 to be most nearly related to Pa. deioarti. 



(5) Ph. maJvaceai'um n. sp. Parasitic on cotton (Gossypium spp.). 

 This organism causes the very characteristic leaf disease known as 

 Atkinson's angular leaf -spot, and also a water-soaked spreading spot- 

 disease of the capsules comparable to that produced on walnuts b}^ 

 Ps. juijlandU and on bean pods })y Ps. pliascoli. This bacterium has 

 nearly the same thermal deatli point as Ps. camj^estris and nuich 

 resembles it in many oth(»r ways. l)ut its slime is more translucent on 

 lX)tato, and it is not parasitic to cabbage. The Avriter has had this 

 organism under o))servation for several years, and has successfully 

 inoculated it into young cotton bolls and leaves. Tissues of the cot- 

 ton plant which are not growing rapidly do not readily contract the 

 disease. This yellow organism is not the same as the green fluorescont 

 germ isolated by Stedman from rotting cotton capsules and named 

 BacUlns gossypina. A full account of the cotton disease is in 

 preparation. 



21788— No. 2s— ol 11 



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