1.
The Parasitic Slime-Moulds.
37
S. subterranea (Wallroth) Lagerheim. (Pl. 16, fig. 1). Wallroth, F. W. Linnæa, Vol. 16. P. 332. 1842. Wallroth, F. W. Beitrage zur Botanik, Vol. 1. Pp. 118-123. 1842. Lagerheim, G. de Journ. Mycol. Vol. 7. Pp. 103-104. 1892. Syn. Erysibe subterranea Wallroth, F. W. Linnæa, Vol. 16. P. 332, 1842.
Protomyces Tuberum-solani Martius, K.P.F. von. Die Kartoffel-Epidemie der letzten
Jahre oder die Stockfäule und Räude der Kartoffeln 1842.
Khidosporium solani Rabenhorst. Leipzig. Pp. 614. 1844.
München. Pp. 70.
Deutschlands Kryptogamen-Flora, Vol. Pilze.
1.
Tubercinia scabies Berkeley, M. J. Journ. Hørt. Soc. Lond. Vol. 5. Pp. 9-34. 1846, Sorosporium scabies Waldheim, A. A. F. von. Apercu Systématique des Ustilaginées.
Paris. Pp. 51. 1877.
Spongospora solani Brunchorst, J. Bergens Muscum Aarsberetnung. 1886. Pp. 219-
226, 1887.
Spongospora scabies Massee, G. Journ. Bd. of Agric., England. Vol. 15. Pp. 592-599.
1908.
Spores 414 in On ger-
44
"
Spore mases irregular in shape, 45μ×70μ in size. diameter, with smooth, thin walls, generally yellow in colour. mination they produce swarm spores which fuse in pairs and give rise to a plasmodium. Plasmodia when mature gives rise to one or occasionally more spore-balls. The organism causes the host tissue to become active, and either produces abnormal development of cork, with a final production of a scab, or, if the root is attacked, a gall about a centimetre in diameter. Various species of the genus Solanum are infected, but it is most common on the cultivated potato. The organism has a world-wide distribution.
This organism is responsible for the disease of potatoes known in this country as "Corky Scab," in France as gale ordinaire
in Italy as "crosta," in Germany as Pulverschorf," in Holland as poederschurft and in Denmark as "pulverskurv." The disease is first apparent as slightly raised pimples and slight discolouration, and when the tubers are cut the infected area is generally purple in colour. When the organism is mature the scabs burst and the spores become scattered. The fungus does not attack those parts of the plant which are above the soil. The distribution of the disease is interesting. After being recorded in England in 1842, it was found in the Netherlands, Belgium, Norway, France, Sweden and Germany. Later it occurred in the United States and Canada, probably as the result of shipments of potatoes from Europe, but it was also found in 1891 by Lagerheim at Quito in Ecuador. He discovered that the disease was well known to the natives, and, since South America is probably the native home of the potato, it suggests that the disease first reached Europe from South Americă, spread through Europe, and from thence into North America. occurs most commonly in countries with a heavy rainfall.
It
2. S. Campanula (Ferdinandsen & Winge), Cook nov. comb. (Pl. 16, fig. 2). Ann. Bot. Vol. 34. Pp. 467- Syn. Clathrosorus campanulæ Ferdinandsen, C. & Winge 0.
469. 1920.
25# 10
Spore masses developed singly in the cortical cells of the host,
50 in diameter. Spores spherical with smooth walls, 4-5μ—5μ
Supplement No. 1, 1932.
in
122
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