Makers of British Botany; a collection of biographies by living botanists

by Unknown

All these ill-grounded hypotheses were swept away in 1844 when Nägeli discovered antheridia containing spermatozoids on the "cotyledon" or pro-embryo of the fern—the prothallus we call it now. Nägeli at once recognised their essential agreement with the antheridia already known in the Bryophytes and compared the spermatozoids with the corresponding structures in animals. But as he overlooked the existence of the archegonia, or rather by some lapse mistook them for stages in the development of the antheridia, it is not surprising that he was at a loss to understand the significance of his discovery, and that he should have commented on his dilemma in the following terms. "Seeing that the female organs (spores) arise on the frond at a much later stage of development, and long after the pro-embryo has died away, the function of the spermatozoids is far from evident."

It was only three years later that light was thrown on the situation, and from an unexpected quarter. Count Suminski, an amateur microscopist, announced the discovery of additional reproductive organs on the fern pro-embryo, which he clearly distinguished from the "spiral filament organs" or antheridia. His full paper, which appeared in 1848, marks an epoch in morphology, and was a very remarkable performance. In it he redescribes the antheridia and spermatozoids—detecting their tufted cilia which Nägeli had overlooked. The archegonia he describes as ovules without envelopes consisting of a papilla (the neck) which becomes perforated, giving the spermatozoid access to the embryo-sac within. His figures of the process of fertilisation are extremely interesting as they show how completely he was dominated by the theory of Schleiden to which allusion has already been made. The head of the sperm is represented as entering the "embryo-sac," and there becoming encysted to form the embryo just as the tip of the pollen tube was supposed to do in flowering plants. The further development of the embryo and its various organs are traced and figured, however, in the most admirable way. At the conclusion of his paper Suminski states that in view of the presence of male organs and ovules, and the occurrence of fertilisation, the cryptogamy of ferns does not exist in a physiological sense, and ceases to have any validity as a peculiar character. A remark which he follows up by the statement that ferns must on the existing classification be referred to the Monocotyledons.

In certain respects no doubt Suminski's paper is fantastic—more especially the circumstantial details given of the process of fertilisation. But, however we may criticise his work the credit belongs to Suminski of showing (1) that sexual organs are borne on the prothallus, (2) that the embryo fern plant is produced as the result of fertilisation. Unlike Nägeli, to Suminski came the happy inspiration of looking for the female organs in the position where common sense indicated they ought to be found.

Suminski's paper instantly aroused universal interest, and the whole of his assertions were at first categorically denied by the German botanist Wigand.

We may now trace Henfrey's attitude to Suminski's work.

His first notice occurs in the body of a review of Lindley's "Introduction" in the first volume of his Botanical Gazette, and shows him to have been profoundly sceptical, if not contemptuous, of the occurrence of fertilisation in the prothallus of the fern. His words are "this (i.e. Suminski's discovery) appears to have little but originality to render it worthy of notice." That appeared in February 1849.

Writing at greater length of Suminski's work in the Annals and Magazine of Natural History, in November of the same year, he speaks much more guardedly. "These researches are in the highest degree curious, and if the facts related prove to be correct, most importantly affect the received views of analogies in the generative processes of plants."

At the same time Henfrey says he hopes to speak more definitely on this matter when his own investigations are complete. Two years later his own very careful work in the same field was laid before the Linnean Society, in which he corroborated the main facts that had come to light. Turning once again to the paper of Suminski, after making certain criticisms of detail, Henfrey handsomely remarks—"Nothing however can take from him the credit of having discovered the archegonia and their import, one of the most important discoveries in physiological Botany of modern times since it has led to results revolutionising the whole theory of the reproduction of plants and opened out a totally new sphere of inquiry into the laws and relations of vegetable life."

For some little time after these discoveries the archegonia of the fern were, on the initiative of Mercklin, commonly referred to as the "organs of Suminski," a custom which happily fell into desuetude. Mercklin, in his paper, which essentially repeats the work of Suminski, states that he devoted his entire attention for three months to the fern prothalli before he succeeded in observing the entrance of a spermatozoid.

In reviewing the early papers of the Hofmeisterian epoch—papers which form the bed-rock of the existing morphology—one is struck with the marvellous rapidity with which their significance was apprehended. We find the phrase "alternation of generations" employed within two years of the discoveries of Suminski, whilst by the early fifties the general genetic relations of the vascular series were realized in quite a new light.