Talk:An Illustrated Flora of the Northern United States, Canada and the British Possessions/Introduction

The following list of rules appeared in the 1st edition, but was omitted from the 2nd edition and so have been removed.

It cannot he too often repeated that the object of these rules is not to introduce new names, but to restore the old and the true ones. The rules of the botanists of the American Association, adopted as above, are as follows. A brief explanation of the objects attained by them is appended:

Rule 1.	Priority of publication is to be regarded as the fundamental principle of botanical nomenclature. This has heen generally acknowledged in theory as the guiding principle for determining which name should he borne by an animal or plant differently named by different writers. Various causes have retarded its application in practice. Its adoption is the only practicable way of securing stability to the onginal names. It has also been generally considered that the author who first defines or describes an animal or plant is entitled to the distinction of having his own name permanently associated with the name assigned to it; and this is also necessary for reasons of accuracy, because in numerous instances different plants have heen called by the same name. In most cases the synonyms given in this work, with the date of publication, indicate the original name and the reason for its restoration under this rule.
Rule 2.	The botanical nomenclature of both genera and species is to begin with the publication of the first edition of Linnaeus' Species Plantarnm in 1753. Some past date must of necessity be taken. in order to fix the limits within which priority shall he reckoned. Prior to the publication of Species Plantarnm in 1753, the absence of any general binomial nomenclature, and the meagre, uncertain and inadequate descriptions by most prior authors, make any earlier date beset with difficulties. The result of much discussion has been to fix that work, with which modern nomenclature substantially begins. as the "point of departure." That date received the endorsement of the International Botanical Congress at Genoa in 1892, and has since been accepted by most botanists in America and Europe. Under this rule, no reference is made to names used prior to that work.
Rule 3.	In the transfer of a species to a genus other than the one under which it was first published, the original specific name is to be retained. From different views of the limits of genera, or from further knowledge of a plant, it often happens that it must be transferred to a different genus from that to which it was first assigned. Upon such a transfer, Rule 3 requires the original name of the species to be continued, and preserves its stability. Thus, out of the genus Polypodium of Linnaeus, three other groups have heen since carved. viz., Dryopleris (Aspidium), Cystopteris and Phegopteris. The Long Beech Fern (p. 19), called Polypodium Phegopteris by Linnaeus, belongs to the generic goup named Phegopteris by Fée in 1850. Rule 3 forbids the use of the new specific name, polypodioides, given to this plant hy Fée, and requires the former specific name of Linnaeus to be preserved, and the plant thus becomes Phegopteris Phegopteris, an accidental re-duplication that occurs in but few instances in the whole field of nomenclature. The Twin-leaf was called Podophyttum dipllyllum by Linnaeus in 1753, and Jeffersonia binata by Barton in 1793; Persoon in 1805 restored the Linnaean specific name, making the plant Jeffersonia diphylla, the correct binomial under the rule, and the one which the plant has borne for nearly one hundred years.
Rule 4.	The original name is to be maintained, whether published as species, subspecies or variety. Plants and animals are continually described as species which subsequent authors conclude are but varieties, and those first understood as varieties prove by subsequent study to be entitled to specific rank. Rule 4 maintains the first designation as the proper one, and avoids much confusion. Examples are numerous: See Figs. 28, 38, 61 et seq.
Rule 5.	The publication of a generic name or a binomial invalidates the use of the same name for any suhsequently published genus or species, respecively. Thus in the case of the Long Beech Fern, above cited, though the specific name polypodioides is held to have been improperly given to it by Fée, the binomial, Phegopteris polypodioides, cannot be applied to any different plant; for if the earlier name should for any reason he lost or discarded, the name polypodioldes must remain available as the next lawful substitute, and thus the principle of nomenclature—once a synonym always a synonym. This rule operates to maintain one name only for a genus or species, and that, the first one applied to it, unless this was properly the name of another, in which case the next oldest By mistake or inadvertently the same name has frequently been given to several different genera or species, and it has repeatedly occurred that a name beleved by the author to be a synonym is shown by another to be a valid designation.
Rule 6.	Publication of a genus consists only, (1) in the distribution of a printed description of the genus named; (2) in the publication of the name of the genus and the citation of one or more previously published species as examples or types of the genus, with or without a diagnosis.
Rule 7.	Publication of a species consists only, (1) in the distribution of a printed description of the species named; (2) in the publishing of a binomial, with reference to a previously published species as a type.
Rule 8.	Similar generic names are not to be rejected on account of slight differences, except in the spelling of the same word. Thus Epidendrum and Epidendron are but different spellings of the same word; only one of them can therefore be used; the same of Elodes and Elodea.
Rule 9.	In the case of a species which has been transferred from one genus to another, the original author must always be cited in parenthesis, followed by the author of the new binomial. Thus Dryopteris Lonichites (L.) Kuntze (Fig. 26) is so cited, because Linnaeus first gave the plant the specific name Lonchites, while Kuntze first combined that name with the accepted genus Dryopteris.
Rule 10.	In determining the name of a genus or species to which two or more names have been given by an author in the same volume, or on the same page of a volume, precedence shall decide.4

The Latin names of families have mostly been adopted as currently used, without reference to priority or terminations, as no rule on that subject has yet been formally adopted by botanists. It seems desirable, however, that the scientific names of families should also follow some uniform system, and as a very large proportion of botanical family names have long been formed by the termination aceae affixed to some prominent genus of the group, that this rule should be applied to the few remaining families otherwise named. All would thus be brought into a harmonious system of nomenclature, as the zoologists have done by the adoption of the ending idae for all zoological families. The English common names of families are similarly adopted from some characteristic genus of the group; as Pink Family, Mustard Family, Mint Family, etc. The Carophyllaceae, in the absence of any genus Caryophytlum, might thus become Alsinaceae, the Cruciferae, Brassicaceae, the Labiatae, Menthaceae or Lamiaceae.