16. Oidium abortifaciens.—The Ergot-mould.

Botanical name: 

Fig. 184. Oidium (Ergotaetia) abortifaciens. Related entry: Spurred Rye or Ergot

History.—Phillipar [Traité Organogr. et Physiologico-agric. sur l'Ergot, Versailles, 1827.], in 1837, recognized the joints or sporidia of this fungus on ergot. Phrebus [Deutschl. kryptog. Giftgewachse, Taf. ix. Berlin, 1838.], in 1838, detected and figured these bodies, but did not consider them to be of a fungic nature. Mr. John Smith [Trans. Linn. Society, vol. xviii. p. 449.], of the Kew Garden, in November, 1838, recognized them on various ergotized grasses. He considered them to be the joints of a minute articulated fungus, from whose action ergot resulted. In December, 1838, the late Mr. E. J. Quekett [Ibid., p. 453. An abridgment of this paper was published in the Lond. Med. Gaz. vol. xxiii. p. 606, Jan. 19, 1839.] gave an extended account of this fungus, in a paper read before the Linnean Society. Mr. Quekett named the plant Ergotaetia abortans (Ergotaetia, from Ergot, and αιτια, origin; abortans, in allusion to its destroying the germinating power of the grain of grasses, and also to the medicinal powers of ergot). Subsequently, at my suggestion, he substituted the word abortifaciens for abortans.

Mr. Quekett at first [See the Lond. Med. Gaz. Jan. 19, 1839.] considered this fungus to belong to the sub-order Hyphomycetes, tribe Mucedines; but after his paper had been read at the Linnean Society, and was returned to him for correction, he was led to suppose that the fungus belonged to the sub-order Coniomycetes, tribe Sporidemiei, because its sporidia were produced beneath the epidermis of the grain. Both Link [Report on the Progress of Physiological Botany in 1841, published by the Ray Society, p. 91.] and the Rev. M. J. Berkeley consider the ergot-mould to be a mucedinous fungus belonging to the genus Oidium (so called from ωον, an egg, and ειδος, resemblance), and I have, therefore, called it, at the suggestion of the last-named eminent fungologist, Oidium abortifaciens. Corda [Beitrag zur Kenntniss der Brandarten der Cerealien und des Mutterkorns, in the Oekonomische Neuigkeiten und Verhandlungen, No. 83, 1946: a periodical publication. I am indebted to the Rev. M. J. Berkeley for the loan of corda's paper. A copy of Corda's figures, illustrating the structure of th ergot of rye, and of the microscopic appearance of the fungus, will be given hereafter (see Secale Cornutum).] has recently referred it to the genus Hymenula, of the sub-order Hymenophycetes, and names it Hymenula Clavus.

Botany. Chen. Char.—Microscopic. Threads white or brightly coloured, simple or irregularly branched, moniliform above, and breaking up into more or less elliptical spores. (Berkeley in Lindl. Med. and Oecon. Bot., p. 14, 1844.)

Sp. Char.—Threads white, irregularly branched; spores abundant, elliptic, containing two nuclei (Berkeley).

Mr. Quekett's description of the ergot-mould (called by him Ergotaetia abortifaciens) is as follows: Sporidia elliptical, moniliform, finally separating, transparent, sometimes slightly contracted about their middle, usually containing one, two, or three, but occasionally as many as ten or twelve well-defined greenish granules. They are, on the average, about 1-4000th of an inch long, and 1-6000th of an inch broad. When placed on glass and moistened with water, they readily germinate or produce other plants, though in various ways, as sometimes by emitting tubes (B), by the development of buds (C), and by the formation of septa across their interior (E, F, G, H).

Hab.—Floral envelopes, and ovaria of grasses: Europe, America.

By the growth of these fungi upon or within the ovarium of grasses, a diseased condition of the ovarium, involving the whole of the embryo, and sometimes partially or wholly the albumen, is produced. This disease, called the ergot or spur, will be described hereafter (see Secale Cornutum). Mr. Quekett [Lond. Med. Gaz. Oct. 8, 141; and Trans. of the Linn. Society, vol. xix. p. 137.] has shown that the sporidia of this fungus are capable of infecting healthy grains of corn, and of ergotizing them.

Properties.—The chemical properties and physiological effects of this fungus are at present quite unknown. We have yet to learn whether the peculiar properties of ergotized grasses depend on the fungi, or on the morbid products of the ovarium.

The Elements of Materia Medica and Therapeutics, Vol. II, 3th American ed., was written by Jonathan Pereira in 1854.