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[Extracted from the LINNEAN SOCIETY'S JOURNAL-BOTANY,
GR A MI NE Æ.
GEORGE BENTHAM, F.R.S
Notes on Gramineæ. By GEORGE BENTIAM, F.R.S.
[Read November 3, 1881.] GRAMINE E, so long believed to be the largest Order amongst Monocotyledons, must now yield the palm to Orchideæ in respect of number of species; but they must still be acknowledged as immensely predominant, as well in individual numbers as in the part they take in the vegetation of the globe. The great majority of Orchideæ are very local, and amongst the few that are spread over wider areas it is frequently only in a few individuals dotted here and there; whilst a considerable proportion of Gramineæ are almost cosmopolitan in their geographical distribution within or without the tropics, often covering the ground with innumerable individuals. Orchideæ are difficult to preserve; collectors bring home but few specimens from their chief stations in tropical lands, and those few often imperfect. Their study is therefore surrounded by many impediments, and, with the exception of the few European ones, is in the hands of very few botanists; whilst Grasses, easily dried, abound in herbaria in specimens readily exhibiting their most essential characters; and every local botanist considers himself perfectly competent to describe as new species or genera suggested only by comparison with the few forms known to him from the same limited locality. The consequence is that amongst the large number of new species of Orchidee described of late years the great majority (always excepting garden hybrids or varieties) appear to be really distinct; whilst the number of bad species and genera of Graminew with which science has been overwhelmed is truly appalling. Looking to the future, it is only probable that the preponderance in number of species of Orchidex over Gramineæ is likely to be greatly increased as well by new discoveries among the former, as by a critical revision of old species of the latter. On the other hand, although the interest in Orchideæ has been so much intensified of late years, as well by the extent to which they are cultivated as by the singularities observed in their fertilizing-apparatus, yet their importance in the study of the history and development of vegetation, and in their application to the nses of man, remains as nothing compared to that of Gramineæ.
This paramount importance of the latter Order in an economical point of view has called forth innumerable treatises, memoirs, and essays on cereals, on forage and other cultivated grasses, on
meadows and pastures, on ornamental grasses, on the physiology and properties of the Order, &c., to which I need not further allude, my present object being merely to consider Grainines with reference to their classification and affinities. In a systematic point of view, the great mistake of Linnæus and the earlier systematists was the attempt to regard the whole spikelet as a single flower, with a calyx and corolla to be compared with those of the more perfect Monocotyledons. Robert Brown, with his usual sagacity, pointed out this and other errors, and first laid down the true principles upon which the Order could best be divided into tribes and genera; but he unfortunately took up the idea that the so-called lower and upper paleæ represented three outer segments of a perianth; and although this theory has long since been proved to be groundless, especially by Hugo Mobl, whose views have been fully confirmed by all subsequent careful observers, yet so great is the authority so deservedly attached to every thing that has issued from the pen of Brown, that his explanation of the structure of the spikelet is still allowed to influence the terminology adopted in generic and specific descriptions.
Shortly after the publication of Brown's Prodromus,' Gramineæ were taken up by several French botanists who had acquired materials, rich for the time, chiefly from North America and the West Indies. Some of these had already been published by Michaux or by Persoon, with more or less of assistance from Louis Claude Richard, to whom the credit of all that is good in Persoon’s ‘Synopsis' as well as in Michaux’s ‘Flora' has been attributed by several subsequent writers. The greatest value is justly attached to all of the elder Richard's observations in every Order that he worked up; and there is no doubt that such assistance as he gave to those two works added much to their importance; but we know that he declined to attach his name to Persoon's Synopsis, chiefly from an unwillingness to sanction the arrangement under the Linnean system, and we are by no means assured that there may not have been other details in both works which he did not concur in. We therefore are not justified in fixing on him a responsibility which he refused to undertake; and the genera and species first published by Michaux or by Persoon should be quoted as theirs and not Richard's, except where Richard's name is expressly attached to them. Michaux’s · Flora' was published in 1803, the first volume of Persoon’s ‘Synopsis : in 1805, both of them therefore antecedent to Brown; but two
other special agrostologists, Desvaux and Palisot de Beauvois, bad ample time to avail themselves of Brown's work. Desvaux published his new genera in a memoir which first appeared in abstract in the 'Nouveau Bulletin de la Société Philomathique' for 1810, and afterwards in full in the first volume of his second 'Journal de Botanique’ in 1813. Between these two periods Palisot de Beauvois published his 'Agrostographie,' in which he undertook a general arrangement of the whole Order, with definitions as well of the old-established genera as of a large number of new ones, including those of his contemporary Desvaux. The majority of these genera have since been adopted ; but his arrangement of them was far too technical and his characters often so vague, that they could in most instances scarcely have been identified, were it not for the names of the species which he refers to them and for the really good analytical drawings accompanying his work. it is, several of his names have been misapplied by subsequent botanists, who have not paid sufficient attention to, or have not seen, those drawings.
A few years later, three eminent botanists undertook the general study of Gramineæ. Kunth at Paris and afterwards at Berlin, Trinius in Germany and afterwards at St. Petersburg, and Nees von Esenbeck at Bonn, afterwards at Breslau, worked more or less contemporaneously, but with little or no communication with each other. Kunth’s ‘Revisio Graminum,' published in 1829 and following years, is a work not only splendidly illustrated, but remarkable alike for the accuracy of detail in the descriptions of species, as for several of the views given of their structure and arrangement. This work, however, is so costly as to be accessible to few botanists, and the more generally known first two volumes of his Enumeratio Plantarum,' containing the Grasses, were unfortunately a far too hasty compilation. He had entered into an agreement with old Cotta for the preparation of a com. pact Synopsis Plantarum on the plan of Persoon's, and had received a considerable sum of money on account of the work; but when it came to the actual drawing it up, Cotta insisted upon its being arranged according to the Linnean system, which Kunth would no more agree to than did the elder Richard in the case of Persoon. The Synopsis or Enumeratio was therefore still in abeyance when old Cotta died; and his successors, not caring for the special plan adopted, insisted on an immediate return for the money advanced ; and I several times heard Kunth himself much
bewail the necessity he was under of getting up these volumes without the care and study he could have wished to bestow on them, and which he did apply to his next volume on Cyperacea. Kunth also in all his works fully adopted Brown's theory as to the homology of the parts of the spikelet, carrying it out in detail to a degree which sometimes amounts almost to a reductio ad absurdum; as, for instance, in Piptatherum and Milium, two genera so closely connected in structure that they are still regarded by many experienced botanists as slightly different sections of one genus. In both genera we see the whole spikelet consist of two similar outer glumes without the slightest rudiment of a flower in their axis, and of a third glume enclosing a flower and its palea ; and yet we are told that whilst in Piptatherum we have two glumes and one flower, we must in Milium consider them as one glume and two flowers.
Trinius published his Fundamenta Agrostographiæ' in 1820, something on the plan of Beauvois’s ‘Agrostographie,' but evidently founded on insufficient materials and bibliographical resources, and with some neglect of the already well-established rules of nomenclature. From that time, however, he devoted himself with the greatest zeal and increasing success to the study of the Order. I heard him say, à propos of some rather costly collection of specimens, that he would willingly sell his last coat for a new grass; and all his later works, down to his last papers worked up in conjunction with Ruprecht, and published in the Memoirs of the Petersburg Academy, are of the greatest value to agrostologists, though he never followed them up by any general synoptical view of the Order. In respect of terminology, he so far modified that of Kunth, that where a glume is theoretically supposed to have a flower in its axil, but really has not even the slightest rudiment, he does not, like Kunth, call 'it a whole (neutral) flower, but only half a flower.
Nees von Esenbeck never confined himself so exclusively to Gramineæ as did Trinius; he never published any general conspectus of the Order, and entered but little into general considerations of their structure and terminology; but he described with great care the grasses of various tropical and other extraEuropean regions; he had ample materials placed at his disposal, from the collections of Martius, Drège, Preiss, and other German travellers, and from the herbaria of Hooker, Arnott, and Lindley in this country, and he came to be regarded as the great autho