A KEY TO STRUCTURAL, PHYSIOLOGICAL, AND SYSTEMATIC BOTANY, FOR THE USE OF CLASSES. BY JOHN LINDLEY, PH. D. F.R.S. L.S. AND G.S. MEMBER OF THE IMP. ACAD. NAT. CUR., BOT. SOC. RATISB., PHYSIOG. PROFESSOR OF BOTANY IN THE UNIVERSITY OF LONDON, AND IN THE LONDON: PRINTED FOR LONGMAN, REES, ORME, BROWN, GREEN, & LONGMAN, PATERNOSTER-ROW. 1835. Verum quod alias dixi illud hic repeto et inculco, non sperandam à me Methodum undequaque perfectam et omnibus suis numeris absolutam, quæ et plantas in genera ità distribuat ut universæ species comprehendantur, nullâ adhuc anomalâ et sui generis reliquâ, et unumquodque genus notis suis propriis et characteristicis ità circumscribat, ut nullæ inveniantur species incerti, ut ita dicam, laris, et ad plura genera revocabilis. Nec enim id patitur natura rei. Nam, cùm Natura (ut dici solet) non faciat saltus, neque ab extremo ad extremum transeat nisi per medium, inter superiores et inferiores, rerum ordines nonnullas mediæ et ambiguæ conditionis producere solet, quæ de utroque participent, et utrosque velut connectant, ut ad utrum pertineant omninò incertum sit. Præterea eadem alma parens in methodi cujuscunque angustias coerceri repugnat, sed ad libertatem et avrovoμíav suam nullis legibus obnoxiam ostentandam, in unoquoque rerum ordine nonnullas species creare solet, tanquam exceptiones à regulis generalibus, singulares et anomalas. — RAII, Hist. Plant. vol. i. Præf. THE idea of this book was suggested to me by the difficulty experienced by all teachers, in explaining to their students what are the most prominent and important points in Botany, on which to fix their attention. I found that when axioms are thrown into an extended and descriptive form, and mixed up with discussions which are only incidental to them, the student is apt to lose sight of the exact nature of the argument, and to confound different phenomena from want of the power of disentangling the more essential from the less essential subjects. It is clear, that, without a distinct perception of the exact nature of the first principles of any science, no one can hope to apply it to practical purposes with any probability of success. These considerations originally led to the publication of my "Outline of the First Principles of Botany," wherein the fundamental propositions upon which the principles of Organic and Physiological Botany depend were stated as briefly as the nature of the subject would permit. The success with which this little. book was received, and its recognised utility to students, whatever its defects may have been, induced me to attempt the far more difficult task of reducing the definitions employed in the higher part of Systematic Botany to their simplest form, and to show that the impediments which accompany this branch of the science are susceptible of being very materially diminished by a careful and extensive kind of analysis. The "Nixus Plantarum” was written with the view of putting to the test the possibility of executing such a plan, and it has been extremely satisfactory to me to find that this work also, although in many respects totally unsuited to the use of students, has nevertheless been in many cases employed by them with singular advantage. As both the "Outline of First Principles" and the "Nixus" are out of print, I have determined to combine them into one work, a sort of Botanical Note-Book, wherein all the principal topics which the teachers of Botany either do, or ought to, introduce into their lectures are arranged methodically. The student will naturally look to his instructor for explanations and illustrations of the work, and for the exposition in detail of those points which in his Note-Book are merely adverted to. In the systematic part, I have endeavoured to secare as much distinctness in all respects as the resources of printing would supply; knowing, from experience, how difficult it is to convey to the mind a clear and distinct impression of any thing which is presented to the eye in a state of confusion. I have also ventured to reform the language of Botanists in some respects, by carrying out their own principles to their full extent; thus securing a more uniform kind of nomenclature, and expressing the value of the names of the classes, orders, &c., in all cases, by the manner Let me add in conclusion, that no student ought to con- ceive himself sufficiently acquainted with Botany, until he can bear an examination in the whole of the structural and physiolo- gical part of this work, and in the systematic part as far as the |