The correspondence of Ferdinand von Mueller: Melbourne Botanic Garden ¶ February 15, 1868. ¶ Sir — ¶ ¶ In compliance with the request conveyed by your telegram of the 12th instant, ¶ I have the honor to submit to the Rust Commission of Adelai...

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68.02.15

Plant names

Aecidium berberidis
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Arrhenatherum elatius
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Puccinia graminis
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Puccinia straminis
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Uredo linearis
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Preferred Citation:

Ferdinand von Mueller to John Barrow, 1868-02-15. R.W. Home, Thomas A. Darragh, A.M. Lucas, Sara Maroske, D.M. Sinkora, J.H. Voigt and Monika Wells (eds), Correspondence of Ferdinand von Mueller, <https://vmcp.rbg.vic.gov.au/id/68-02-15>, accessed September 11, 2025

Letter not found. The text given here is from 'Report of commission appointed by the Governor-In-Chief to inquire and report upon the diseases in cereals… ' (B68.04.05). A more accessible copy is in 'Diseases in wheat Commission', South Australian chronicle and weekly mail , 20 June 1868, p. 3 (B68.06.07).

The Commissioners' report is published, without the appendices, in 'The rust in wheat commission', South Australian chronicle and weekly mail, 11 April 1868, p. 8.

The Commission resolved on 25 February 'That the Secretary write to Dr. Mueller, conveying the thanks of the commission for the valuable information forwarded by him' (Minutes, p. xi). Letter not found.

Melbourne Botanic Garden

February 15, 1868.

Sir —

In compliance with the request conveyed by your telegram of the 12th instant,

Telegram not found.

I have the honor to submit to the Rust Commission of Adelaide, the principal results of microscopic investigation on the rust fungus occurring in wheat, these resting mainly on the observations of Professor Tulasne of Paris,

See, for example, Tulasne (1853), Tulasne (1854).

and particularly on the still more recent discoveries of Professor de Bary

De Bary (1866).

of Hull.

Halle?

Some of these luminous and important observations I have been able to renew here, and I cannot praise too highly the profound researches displayed by these great mycologists, in reference to this subject.

Two uredinous fungi more especially infest the wheat, and , which in certain stages of development, represent the and the , regarded formerly as distinct fungi.

These in their mode of development, pass through several stages. The most destructive of these two, , or the striped rust, appears early in the summer, in small oblong spots, which are apt to flow in lines together. They arise from a mycelium which ramifies in the cellular tissue beneath the epidermis of the cereal, and thus serves the nutrition of the fungus on the expense of the affected plant. In advancing to its first stage of fructification the epidermis bursts, and oval red-brown stalked spores, now designated summer spores, or uredo spores, protrude; the spores seceding from their stalks, and new stalked spores being produced in succession, again to be washed away by rain, or to be wafted away by the air, or to be carried about by insects.

These particular kinds of spores have the power of immediate germination, and retain it for some weeks. They may germinate in a moist medium within a few hours, each spore pushing forth an elongated cell, which, rootlike, penetrates into any one of the stomata of the epidermis, and ramifies in the cellular tissue beneath, to form a new mycelium. Ripe spores, of the original kind, are produced from the new mycelium so formed, in comparatively a few days. But after a rapid succession of this form of reproduction the fungus passes into another stage. Towards autumn a second kind of spores, now distinguished as autumnal spores, or teleuta

misreading of teleuto?

spores are at first promiscuously developed with the summer spores, but subsequently autumnal spores solely; and as their color is darker, the red-brown of the rust fungus verges, by the gradual prevalence of the autumnal spores, into a darker color, into almost black. These autumnal spores are distinguished by greater size, are generally in a pair, one above the other, terminating the stalk without seceding from it; they are also characterised by stronger cell-walls.

These autumnal spores do not germinate before the next spring, in cold climes.

In spring each of these two telento

misreading of teleuto?

spores send forth an articulated stalk-like protomycelium, from each joint of which stalked sporidia arise, the ripening sporidia breaking from their stalks, while the mycelium perishes. These sporidia are much smaller than the spores, and also far more tender.

The formation of protomycelium and sporidia is completed most rapidly, the only condition for development being moist warm air. The tender sporidia germinate immediately, and with the greatest facility, and what may appear marvellous, their development now, not takes place on wheat or any other cereal, or even grass of any kind, but on some other plant. Professor de Bary has traced, as yet, the development of these sporidia in middle Europe, only on the leaves of the berberry bush, while here in Australia the mystery of their growth has not yet been penetrated, and it thus remains to be ascertained on what especial plants these sporidia find a genial location for this stage of life of the rust fungus.

The sporidia produce by downward growth, a mycelium, rootlet-like; but their off-shoot passes not through the stomata of the berberry leaf, but perforates the walls of any of the epidermis cells, within which they ramify, and then force themselves into the deeper tissue to form a new mycelium. This latter sends out in one or two weeks, a fourth kind of reproductive organ, and called decidium, and formerly regarded as an absolutely distinct fungus, accompanied by peculiar accessory organs called spermagonia. The aecidia are orange-colored cup like vessels; their wells are cellular, and from the bottom of the aecidium arise numerous little stalks, each bearing a simple and rather long series of again peculiar spores. The aecidia are first buried under the epidermis, but burst through it at the moment of fructification. These vernal or aecidium spores separate from their strings readily on ripening, and then resemble the summer spores in structure, in mode and in time of development, passing, like them, through the stomata, and forming mycelium beneath the epidermis, but the next progeny produced from these aecidium spores, are the ordinary uredo spores. The first growth of the uredo state of the fungus may not be on wheat, as the spores may seize on many kinds of grasses, and from them in successive development may only attack the crop. Hence the imperative necessity of clearing as far as possible any growth of weeds and natural grasses at and around the cornfields; a necessity which, to every rational farmer, also for other reasons is obvious. Maize, millet, English rye-grass, and also French rye-grass ( ), are not generally attacked by the rust fungus of wheat. Raised on strips of land, these will form an additional safeguard. Stubbles, I might add, should be carefully burnt, and farm-yard manure destined for the wheatfield be previously well decomposed.

The summer spores of may form conspicuous rootlets or mycelium cells in two or three hours. They ripen a harvest of spores in about eight days. If the before-mentioned sporidia fall on the cereals or other grasses, on which the summer and autumn spores delight to luxuriate, they die off speedily, and if plants for which they rely for their subsistence could be completely extirpated, the cycles of development of this particular rust fungus would be disrupted, and immediate contact locally prevented, though still the field may be subject to the influx of fungus spores from the distance. Unfortunately one single plant of wheat, it has been calculated, may produce several hundred thousand autumnal spores, of which each early in the next culture season may multiply into three or four sporidia. The Puccinia holds its winter quarter copiously on some of the native grasses.

Very common is also the , or the spotted rust in wheat. It forms smaller spots, not so readily flowing together into streaks. The summer spores, or uredo spores, are globular, not oval or pear shaped. The powdery masses of these spores are more red. The autumnal spores do not burst through the epidermal integument, but remain buried beneath, not even swelling the epidermis. In their aggregate they appear finally as minute opaque black spots. The stalk of the spores is shorter than in . This particular fungus is also a parasite on all cereal except maize and millets. It occurs likewise on many fodder and wild grasses. Its development is still somewhat more rapid than that of . The plants on which its autumnal spores germinate as well its acidia, are as yet entirely unknown, for neither these autumnal spores germinate on cereals. is not limited to a few months for producing its summer spores, but germinates the uredo spores throughout the year in continued succession.

In conclusion it is scarcely necessary to remark that it was well known already to the ancient Greeks and Romans, and has ever since been confirmed, that a very wet season will call extensively forth the latent germs of the rust fungi, but the elements of the disease, and certain other conditions predisposing for its development, must exist to render it widely destructive. The most limited observations will impress us with the fact, that not all soils and positions are affected alike, that not all fields worked and manured differently suffer alike, that not all varieties of our principal cereals are succumbing alike. The climatic influences we cannot hope to bring under our control, but we may patiently trace out through microscopic anatomy and biology, and through chemical science, many of the collateral unfortunate conditions on which, irrespective of a wet season, the real devastations of rust depend, and the measures which in tillage, should be adopted to lessen, or perhaps avoid the destruction.

I have the honor, &c,

Fred.

Typesetters error for Ferd.?

von Mueller, M.D., F.R.S.

The Honorable the Chairman of the Diseases in Cereal Commission of Adelaide.

In this document I have not referred to the results of chemical investigations in reference to the rust disease, nor to the choice of grain for seed nor to drainage and many other important subjects bearing on this question, as these, observations are recorded in a report promised to the Victorian Board of Agriculture. This report, as well as the print of a lecture having reference to these subjects,

Neither the report (which has not been found) nor the text of the lecture (B65.04.05) is included in the Parliamentary Paper.

I have the honor of transmitting to the Adelaide Rust Commission, simultaneously with this letter.

Dr .v. M.

The South Australian chronicle and weekly mail, 4 July 1868, p. 11 reports 'Dr. Mueller, of the Melbourne Botanic Gardens, has addressed a letter to the Rust in Wheat Commissioners, acknowledging receipt of copy of their report and appendix, and testifying in terms of high commendation to the value of their investigations.' Neither M's letter nor his copy of the report has been found.