Nomenclature, Accentuation of Names, etc.—In case of question respecting the proper name to be adopted for any species, Dr. Gray's known and expressed views have been followed, it is believed, throughout the work. While reasonable regard has been paid to the claims of priority, the purpose has been to avoid unnecessary changes, in the belief that such changes are in most cases an unmitigated evil. Synonyms are rarely given except where changes have been made. As a guide to correct pronunciation, the long sound of the accented vowel (modified often in personal names) is indicated, as heretofore, by the grave accent (`), and the short sound by the acute (´). In regard to the derivations of generic names, many valuable suggestions have been due to W. R. Gerard, Esq., of New York.
Prominent Characters are indicated by the use of Italic type for the leading distinctions of the Orders, and generally in the specific descriptions for those points by which two or more nearly allied species may be most readily distinguished. The ready discrimination of the genera is provided for by a Synopsis of their leading characters under each order. Whenever a genus comprises several species, pains have been taken to render important differences conspicuous by proper grouping, and when needed by a series of subordinate divisions and subdivisions. The headings of these various groups are to be considered as belonging to and forming a part of the specific characters of the several species under them,—a fact which the student should always bear in mind.
Arrangement of the Orders.—The Natural Orders are disposed in very close accordance with the method followed by Bentham and Hooker in the Genera Plantarum, the principles of which are concisely shown in the Synopsis of Orders which precedes the Analytical Key. The Gymnospermæ are retained as a Subclass following the Angiospermous Dicotyledons, with which they have an obvious relationship, in preference to placing them, as some authorities would do, next before the Pteridophytes, to which their affinity, if no less certain, is nevertheless obscure. A more natural arrangement than either would be the withdrawal of the Endogens, placing them at the beginning, in perhaps an inverse order.
Analytical Key to the Orders.—As stated in Dr. Gray's Preface to the last edition, this is designed to enable the student to refer readily to its proper Order any of our plants, upon taking the pains to ascertain the structure of its flowers, and sometimes of the fruit, and by following out a series of easy steps in the analysis. It is founded upon the most obvious distinctions which will answer the purpose, and is so contrived as to provide for all or nearly all exceptional instances and variant cases. Referring to the Order which the Key leads him to, the student will find its most distinctive points brought together and printed in Italics in the first sentence of the ordinal description, and thus can verify his results. The Synopsis which follows will then lead him to the genus, to be verified in turn by the full generic description in its place; and the progress thence to the species is facilitated, when there are several to choose from, by the arrangement under divisions and subdivisions, as already explained.
It will be seen that the Key directs the inquirer to ascertain, first, the Class of the plant under consideration,—which, even without the seeds, is revealed at once by the plan of the stem, as seen in a cross-section, and usually by the veining of the leaves, and is commonly confirmed by the numerical plan of the flower;—then, if of the first Class, the Subclass is at once determined by the pistil, whether of the ordinary kind, or an open scale bearing naked ovules. If the former, then the choice between the three Divisions is determined by the presence or absence of the petals, and whether separate or united. Each Division is subdivided by equally obvious characters, and, finally, a series of successively subordinated propositions,—each set more indented upon the page than the preceding,—leads to the name of the Order sought for, followed by the number of the page upon which it is described in the body of the work.
The book is now submitted to those for whose benefit it has been prepared, in the trust that its shortcomings will meet with friendly indulgence, and with the earnest request that information be kindly given of any corrections or additions that may appear to be necessary.
SERENO WATSON.
Cambridge, Mass., Dec. 26, 1889.
SYNOPSIS OF THE ORDERS OF PLANT
DESCRIBED IN THIS WORK.
Series I. PHÆNOGAMOUS or FLOWERING PLANTS: those producing real flowers and seeds.
Class I. DICOTYLEDONOUS or EXOGENOUS PLANTS.
Stems formed of bark, wood, and pith; the wood forming a zone between the other two, and increasing, when the stem continues from year to year, by the annual addition of a new layer to the outside, next the bark. Leaves netted-veined. Embryo with a pair of opposite cotyledons, or in Subclass II. often three or more in a whorl. Parts of the flower mostly in fours or fives.
Subclass I. ANGIOSPERMÆ. Pistil consisting of a closed ovary which contains the ovules and becomes the fruit. Cotyledons only two.
Division I. POLYPETALOUS: the calyx and corolla both present; the latter of separate petals. (Apetalous flowers occur in various Orders, as noted under the subdivisions.)
A. THALAMIFLORÆ. Stamens and petals hypogynous (free both from the calyx and from the superior ovary), upon a usually narrow receptacle (not glandular nor discoid, except in Reseda, sometimes stipe-like). (Stamens and petals upon the partly inferior ovary in some Nymphæaceæ.) Apetalous flowers occur in the Ranunculaceæ and Caryophyllaceæ.
[*] 1. Carpels solitary or distinct (or coherent in Magnoliaceæ); sepals and petals deciduous (except in Nymphæaceæ); leaves alternate or radical, without stipules (sometimes opposite or whorled and rarely stipular in Ranunculaceæ); embryo (except in Nelumbo) small, in fleshy albumen.
1. Ranunculaceæ (p. 34). Sepals (3 or more), petals (as many, in regular flowers, or none), stamens (usually many), and carpels (1–many) all distinct. Fruit achenes, follicles, or berries. Mostly herbs.
2. Magnoliaceæ (p. 49). Sepals and petals colored alike, in three or more rows of three, imbricate. Fruit cone-like, formed of the numerous cohering pistils. Trees.
3. Anonaceæ (p. 50). Sepals (3) and petals (6, in two rows) valvate. Fruit pulpy. Shrubs or small trees.
4. Menispermaceæ (p. 51). Sepals and petals in twos or threes, imbricate. Pistils becoming 1-seeded drupes. Diœcious woody climbers, with palmate or peltate leaves.
5. Berberidaceæ (p. 52). Sepals and petals imbricate, each in two rows of three (rarely in twos or fours). Stamens opposite the petals. Pistil solitary, becoming a berry or pod. Shrubs or low herbs.
6. Nymphæaceæ, in part (p. 54). Sepals and petals each 3, or many in several rows. Pistils becoming coriaceous and indehiscent. Aquatics; floating leaves peltate.
[*] 2. Carpels (2 or more) united into a compound ovary with parietal, often nerve-like placentæ (or the seeds covering the inner surface in Nymphæaceæ, and the placentæ axile in Sarraceniaceæ). Herbs (some Cistaceæ somewhat shrubby).
[+] Fruit 5–many-celled; calyx or whole perianth persistent; embryo small, at the base of fleshy albumen.
6. Nymphæaceæ proper (p. 54). Sepals 2–6. Petals and stamens numerous, on a thick hypogynous receptacle