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which vegetables are constructed, or to the external appearance their elementary organs assume in a state of combination. It is exceedingly desirable that these topics should be well understood, because they form the basis of all other parts of the science. In physiology, every function is executed through the agency of the organs : systematic arrangements depend upon characters arising out of their consideration; and descriptive Botany can have no logical precision until the principles of Organography are exactly settled. A difference of opinion exists among the most distinguished botanists, upon some points connected with this subject, so that it has been found expedient to enter occasionally into much detail, for the purpose of satisfying the student of the accuracy of the facts and reasonings upon which he is expected to rely.

To this succeeds VEGETABLE PhysioLOGY (Book II.); or the History of the vital phenomena that have been observed both in plants in general, and in particular species, and also in each of their organs taken separately. It is that part of the science which has the most direct bearing upon practical objects. Its laws, however, are either unintelligible, or susceptible of no exact appreciation, without a previous acquaintance with the more important details of Organography. Much of the subject is at present involved in doubt, and the accuracy of some of the conclusions of physiologists is inferred rather than demonstrated; so that it has been found essential that the grounds of the more popularly received opinions, whether admitted as true or rejected as erroneous, should be given at length.

Next follows GlossoLOGY (Book III.); or, as it was formerly called, TERMINOLOGY; restricted

to the definition of the adjective terms, which are either used exclusively in Botany, or which are employed in that science in some particular and unusual sense. The key to this book, and also to the substantive terms explained in Organography, will be found in a copious index at the end of the volume.

These topics exhaust the science considered only with reference to first principles; there is, however, another which it has been thought advisable to append, on account of its practical value, namely PHYTOGRAPHY (Book IV.); or, an exposition of the rules to be observed in describing and naming plants. As the great object of descriptions in natural history, is to enable every person to recognise a known species, after its station has been discovered by classification, and also to put those who have not had the opportunity of examining a plant themselves into possession of all the facts necessary to acquire a just notion of its structure and affinities; it is indispensable that the principles of making descriptions should be clearly understood, both to prevent their being too general to answer the intended purpose, or more prolix than is really requisite. It is the want of a knowledge of these rules that renders the short descriptions of the classical writers of antiquity, and the longer ones of many a modern traveller, equally vague and unintelligible. In this place are inserted a few notes upon the formation of an herbarium.

It has been my wish to bring every subject that I have introduced down, as nearly as possible, to the state in which it is found at the present day. In doing so, I have added so very considerable a quantity of new matter, especially in what relates to

Vegetable Anatomy and Physiology, that the present edition may be considered, in those respects, a new work.

In the statements I have made, it has been my wish to render due credit to all persons for the discoveries by which they may severally have contributed to the advancement of the science; and if I have on any occasion either omitted to do so, or assumed to myself observations which belong to others, it has been unknowingly or inadvertently. It is, however, impracticable, and if practicable it would not be worth while, to remember upon all occasions from what particular sources information may have been derived. Discoveries, when once communicated to the world, become public property : they are thrown into the common stock for mutual benefit; and it is only in the case of debatable opinions, or of any recent and unconfirmed observations, that it really interests the world that authorities should be quoted at all. In the language of a highly valued friend, when writing upon another subject, — “ The advanced state of a science is but the accumulation of the discoveries and inventions of many: to refer each of these to its author is the business of the history of science, but does not belong to a work which professes merely to give an account of the science as it is : all that is generally acknowledged must pass current from author to author.” *

London, May, 1839.

* Brett's Principles of Astronomy, p. v.

CONTENTS.

80

85

Axis

-

302

- 304

ness

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Page 1

Page

Mosses and Andræaceæ - 265 Hydrocyanic Acid

- 388

Jungermanniaceæ and Hepa Char. XIII. Circulation - 389

ticæ -

- 268

Perspiration -

389

Lichens

270

Rotation - - 591

Algaceæ

272

Cyclosis -

393

Fungacea

- 274 Course of Sap - 400
Circulating Vessels

401

Cause of Motion - • 402

BOOK II. — Physiology.

Chap. XIV. Directions - 406

General Considerations - 277

Chap. XV. Irritability . 418

Chap. I. Chemical Constitution

Poisons - - . 419

of Elementary Organs - 289

Chap. XVI. Colour - . 427

Chap. II. Elementary Organs - 296

Chlorophyll

. 429

Chap. III. Symmetry

Xanthic and Cyanic Series - 432

CHAP. IV. Root .

Marquart's Views - - 434

Chap. V. Stem

. 438

and Origin

Chap. XVII. Odours

Wood . . . 309

Chap. VI. Leaves

324 BOOK III. -- GlosSOLOGY.

Chap. VII. Bracts

330

Calyx and Corolla

330

Absolute Terms - - 445

Disengagement of Caloric - 333

- of Figure . - 446

Chap. VIII. Fertilisation - 337

- of Outline - - 455

Sexuality of Plants denied - 345 - of Apex

. 458

Mules - - - 348

- of Marginal Division - 460

Chap. IX. Fruit . . 351

of Incision . - 461

Changes during ripening - 354

of Composition . 463

Bletting-

356

of Marking or Even-

CHAP. X. Seeds .

358

Their Longevity . - 358

- of Superficial Append-

Germination - 359. 363

ages - - - 468

Respiration

360

of Polish or Surface 471

Action of Heat

S61

of Texture or Substance 471

Chap. XI. Food of Plants - 366

of Size -

- 473

Carbon

- 366

of Duration - . 475

Water

- 367

- of Colour - - 477

Nitrogen -

. 368

- of Variegation . 481

Power of Solution

- 369

of Veining

- 482

Exhaustion of Soil - 370 Relative Terms

. 483

Manures - - . 371

- Estivation

. 483

Chap. XII. Digestion . - 372

- Direction -

Decomposition of Carbonic

· Insertion

- 489

Acid

-

- 373

Collective Terms

- 491

Fungi -

- 378

- Arrangement

- 491

Hydrogen

- 379

- Number :

495

Nitrogen

- 379 Qualifying Terms

Foreign Matter

380

Signs

. 496

Light

- 382 Abbreviations :

- 499

Excretions -

- 389

Nitrogen

· 385

BOOK IV. - PHYTOGRAPHY.

Hydrogen

- 385

Sulphurous Acid Gas

- 385

Chap. I. Diagnoses - - 507

Muriatic Acid Gas

- 386

Differential Characters - 508

Chlorine

-

- 386 Essential Characters 508

Nitrous Acid Gas

- 386 Chap. II. Descriptions

- 514

Sulphuretted Hydrogen 386 Chap. III. Punctuation - 526

Ammonia -

387 Chap. IV. Nomenclature - 528

387

Terminology

- 532

Carbonic Oxide .

- 387 Chap. V. Synonyms

. 534

Olefiant Gas

- 388 Chap. VI. Herbaria . - 537

Protoxide of Nitrogen - 388 Chap. VII. Botanical Drawings 544

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