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FUNGI PARASITIC ON VACCINIUM VITIS-IDÆEA.
By W. T. Thiselton Dyek, B.A., B.Sc.
Certain gall-like bodies occurring on Rhododendron ferrngineum, as to the origin of which opinions are somewhat divided, have recently been the subject of some discussion in the pages of the 'Gardener's Chronicle.' In the number for August 5, the Rev. M. J. Berkeley remarks in reference to them, " Mr. Broome has recently sent from Perthshire a thinner but similar substance on Vaccinium Vitis-Idæa covered with a similar bloom. There is no reason to suppose this is an insect product."
About the mi(hlle of the same month I met with plants of Vaccinium Vitis-Idæa, affected in the way described near the Trossachs, and therefore in the same county in which Mr. Broome also met with it. I submitted a specimen to Mr. Berkeley, who informed me that it was the result of "some species of Ascomyces, probably the same which accompanies or causes the gall-like bodies on Rhododendron ferrugineum." These he had already attributed (Gard. Chron., July 22, p. 944) to an Ascomyces, similar to that (A. deformans, Berk.) which produces blister in Peach-trees.
Happening to show a Vaccinium affected in this way to Dr. Ascherson, of Berlin, he at once identified it as the effect of a fungus, Exobasidium Vacinii, Woronin, and informed me that it was frequently met with in Germany. In Rabetdiorst's 'Fungi Europæei,' there are authentic speci- mens from AVoronin, gathered near St. Petersburg. The fungus was, however, originally described by Fuckel in the ' Botanische Zeitung ' for 1861, p. 251, and he figures (tab. x. t. 7) a portion of the affected Vacclniimi, and also the spores. He gave it the name of Fusidium Vaccinii, and published specimens with that name in his 'Fungi Rhenani' (n. 221). I learn from Mr. Cooke that the same plant was collected a quarter of a century ago by Dr. Greville, and named in MS. Cylindrosporium deformans, but not described. In 1867, however, Woronin published an elaborate paper, illustrated with beautiful plates, contained in the fourth volume of the 'Berichte über die Verhaudlungen der Naturforschenden Gescllschaft zu Freiburg im Breissgau,' (pp. 397-416, t. v. vi. vii.) in which he states (p. 400) that while entirely agreeing with Fuckel that the dis- eased state of the Vaccinium is produced by a parasitic fungus, and not through the punctures of insects, he considers the fungus to be alto- gether different from a true Fusidium. He also remarks that while Fuckel had met with the fungus on both Vaccinium Vitis-Idæa and V. Myrtillus, he has only succeeded in finding it on the first of these plants. Woronin represents in his figures the fungus as attacking, besides the leaves, the twigs (f. 11, 12, 13), and also the flowers (f. 16, 17, 18). The parts aft'ected become much hypertrophied, of a pinkish-white colour, and with a fiocculeut-looking surface. In a microscopic examination of a section, the intervals between the cells are seen to be densely filled with a mycelium from which clavate cells (basidia) are protruded through the epidermal layer of the part of the plant affected. These basidia bear the spores on short stalks. As remarked by Woronin (1. c. p. 412) Exobasidium must necessarily be included amongst the Hymenomycetes. "It stands in the same relation to the Hymenomycetes (Basidiomycetes) as the genus Exoascus [Ascomyces] to the Discomycetes (Ascomycetes).[1] Fuckel only
- r2 Fasidium tumescens, Fckl. 1. c. p. 371, Fungi Rh. 1653, which also occurs on Vaccinium Vitis-Idæa, may possibly belong to Calyplospora Gæppertiana, Kuhn.
- ↑ There is an abstract of Woronin's paper in 'Hedwigia,' 1867, pp. 150, 151.
