Читать книгу Grasses: A Handbook for use in the Field and Laboratory - H. Marshall Ward - Страница 3

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THE following pages have been written in the hope that they may be used in the field and in the laboratory with specimens of our ordinary grasses in the hand. Most of the exercises involved demand exact study by means of a good hand-lens, a mode of investigation far too much neglected in modern teaching. The book is not intended to be a complete manual of grasses, but to be an account of our common native species, so arranged that the student may learn how to closely observe and deal with the distinctive characters of these remarkable plants when such problems as the botanical analysis of a meadow or pasture, of hay, of weeds, or of “seed” grasses are presented, as well as when investigating questions of more abstract scientific nature.

I have not hesitated, however, to introduce general statements on the biology and physiological peculiarities of grasses where such may serve the purpose of interesting the reader in the wider botanical bearings of the subject, though several reasons may be urged against extending this part of the theme in a book intended to be portable, and of direct practical use to students in the field.

I have pleasure in expressing my thanks to Mr. R. H. Biffen for carefully testing the classification of “seeds" on pp. 135−174, and to him and to Mr. Shipley for kindly looking over the proofs; also to Mr. Lewton-Brain, who has tested the classification of leaf-sections put forward on pp. 72−82, and prepared the drawings for Figs. 21−28.

That errors are entirely absent from such a work as this is perhaps too much to expect: I hope they are few, and that readers will oblige me with any corrections they may find necessary or advantageous for the better working of the tables.

The list of the chief authorities referred to, which students who desire to proceed further with the study of grasses should consult, is given at the end.

I have pleasure in acknowledging my indebtedness to the following works for illustrations which are inserted by permission of the several publishers:—Stebler’s Forage Plants (published by Nutt & Co.), Nobbe’s Handbuch der Samenkunde (Wiegandt, Hempel and Parey, Berlin), Harz’s Landwirthschaftliche Samenkunde (Paul Parey, Berlin), Strasburger and Noll’s Text-Book of Botany (Macmillan & Co.), Figuier’s Vegetable World (Cassell & Co.), Lubbock’s Flowers, Fruits and Seeds (Macmillan & Co.), Kerner’s Natural History of Plants (Blackie & Son), and Oliver’s First Book of Indian Botany (Macmillan & Co.).

It is impossible to avoid the question of variation in work of this kind, and students will without doubt come across instances—especially in such genera as Agropyrum, Festuca, Agrostis and Bromus—of small variations which show how impossible it is to fit the facts of living organisms into the rigid frames of classification. It may possibly be urged that this invalidates all attempts at such classifications: the same argument applies to all our systems, though it is perhaps less disastrous to the best Natural Systems which attempt to take in large groups of facts, than to artificial systems selected for special purposes. Perhaps something useful may be learned by showing more clearly where and how grasses vary, and I hope that the application to them of these preliminary tests may elucidate more facts as we proceed.

H. M. W.

Cambridge, April, 1901.