Plasmodiophora Woronin
- 1879. Plasmodiophora Woronin, Pringsh. Jahrb., XI., p. 548.
Parasitic in the parenchymatous cells of the roots of living plants, causing noticeable enlargement of the affected organ, producing at length galls, knots, and various deformities and distortions. Spores spherical, smooth, colorless, 16 µ.
I. Plasmodiophora brassicæ Woronin.
- 1879. Plasmodiophora brassicae Woronin, op. cit.
This species, typical of forms so far reported in this country, infests the roots of cabbages,[15] and produces a very serious disease of that vegetable. In England the malady has long been known under the names "clubbing," "fingers and toes," etc. The roots affected swell greatly, and at length resemble sometimes the flexed fingers of the human hand; hence the English name. As the disease progresses, the roots speedily rot away, to the serious injury of the leaf-bearing portion of the plant. In badly affected fields, sometimes one-half of the crop is utterly destroyed. Careful search continued through several years has not availed to bring this species to my personal acquaintance.
For a full account of the parasitism of this species and its distribution in the United States see Jour. Myc., VII., p. 79; also Bull. 66, Agric. Sta. of Vermont.
Sub-Class EXOSPOREÆ Rost.
- 1873. Exosporeae Rostafinski, Versuch, p. 2.
Spores developed, superficially, outside the fructification, which consists of sporophores, membranous, or slender and branching; spores white, stalked. A single genus,—