to all known rules. "When Zoology," says Mr. Milne Edwards, "is only studied in systematic works, it is often supposed that each class, each family, and each genus, present to us boundaries precisely defined, and that there can be no uncertainty as to the place to be assigned, in a natural classification, to every animal the organisation of which is sufficiently known. But when we study this science from Nature herself, we are soou convinced of the contrary, and we sometimes see the transition from one plan of structure to an entirely different scheme of organisation take place by degrees so completely shaded one into the other that it becomes very difficult to trace the line of demarcation between the groups thus connected."—Ann. Sc. Nat. 1840, Sept. Ray long ago pointed this out in a very remarkable passage, which cannot be too often quoted. "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, nulla 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 revocabiles. 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 avтovoμíav 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.) Linnæus did but copy this when he asserted that Nature makes no leaps (Natura non facit saltus.-Phil. Bot. 77.) This doctrine has, however, been lately called in question by no less eminent a writer than M. Alphonse De Candolle, who requires that absolute limits should be assigned to all groups of whatever degree. "If," he says, "we cannot state in what respect two families differ permanently and universally, those two families are but one. Two pieces of land which touch each other form one island, and not two; but two pieces of land which are separated by an arm of the sea, form two islands, and not one." -Annales des Sciences, series 3, vol. 1. p. 254. But this is a kind of reasoning wholly inapplicable to Natural History, for the reasons so admirably given by Ray, and is contrary to all experience. If the groups limited by M. Alphonse De Candolle himself are examined by this standard they alone suffice to demonstrate how visionary are such expectations. Mr. Bentham has satisfactorily answered the learned Botanist of Geneva. "We Botanists," he says, "cannot be so mathematically exact as geographers, and where an isthmus is very narrow, we must class the peninsula with the island. How often does it happen that two large Orders, say of five hundred to two thousand or three thousand species, totally distinct from each other in all those species by a series of constant characters, are yet connected by some small isolated genus of a dozen, half a dozen, nay a single species, in which these very characters are so inconstant, uncertain, or variously combined as to leave no room for the strait through which we ought to navigate between the two islands."-London Journal of Botany, 4. 232. It would be very convenient to find that the views of M. Alphonse De Candolle were practicable, but in truth they are quite Utopian. While, however, the impracticability of absolute definitions is thus insisted upon, there can be no doubt that much more precision may be introduced than is too frequently found among them. Exceptions, although to some extent inevitable, are not uncommonly apparent, not real. It will frequently be found that a particular species is at variance with the definition of its Genus, or of a Genus with that of its Order, or of an Order with that of its Alliance; but, upon a full examination of all the structure of such supposed exceptions, it will turn out that they are misplaced, and do not in fact belong to the station which they occupy. Exceptions of this kind were formerly very common, but they are disappearing under the diligent criticism of modern observers. The genus Rhynchotheca may be taken as an example. The great feature of the Cranesbills is their beaked torus and folded-up embryo, and it is by that circumstance that they are essentially distinguished from their neighbours. But Rhynchotheca was described as having a beaked fruit and straight embryo; it therefore formed an apparent exception to the definition of Cranesbills. Investigation of the plant has however shown that its beak belongs to the carpels and not to the torus; and, therefore, it is merely an Oxalid, with a tendency towards the structure of a Cranesbill. The manner in which the foregoing principles have been applied to practice has differed greatly, and the result has been schemes of various degrees of merit, some of which have dropped still-born from the press, while others continue to enjoy a well-deserved reputation. It would be alike unjust to their authors and the public to omit all mention of even the most obscure of these, each of which has been the result of much thought and patient study, and has doubtless contributed something to the progress of systematic science. But it would be beyond the object of the present sketch to treat them all at length, nor would the student derive any advantage from doing so. While, therefore, the following pages will be occupied by some account of every plan for a Natural classification of which I have any knowledge, since the year 1789 inclusive, and of those of Ray and Linnæus of an earlier date, such as are comparatively unimportant will be dismissed in a few words, and those only which have been really employed in practice will be stated at length. In order to render the latter more useful, references are given to the pages in the present work where an account of each Order may be found; so that those who are accustomed to the use of other systems may not experience inconvenience from the arrangement proposed in the work now submitted to their consideration. *I do not, however, include the arrangements of the German Naturphilosophists; not, indeed, from any disrespect to those learned men, but because I must confess my inability to master their ideas, or to comprehend how their views are made applicable to any intelligible classification. The student will, I believe, find full information upon the subject in Oken's Lehrbuch der Naturphilosophic, edition of 1843. See also Reichenbach's Conspectus Regni Vegetabilis, 1828, the same author's Flora Germanica Excursoria, 1830-2, and Schultz Futurliches System des Pflanzenreichs, 1832. NATURAL SYSTEMS. [Where references are given after the names of Orders, in this part of the present work, they refer to the page where such Orders are to be found in the succeeding sheets]. 1703. RAY, John.-(Methodus Plantarum emendata et aucta). Here we have the germ of the present methods of natural arrangement. In fact the first divisions of the Vegetable Kingdom, proposed by Ray, are identical with those of Jussieu. Like him, he proceeded from the more imperfect to the most highly organised forms; the only difference being that he placed Dicotyledons before Monocotyledons. The author's words are " Floriferas dividemus in dicotyledones, quarum semina sata binis foliis anomalis, seminalibus dictis, quæ cotyledonum usum præstant, è terrâ exeunt, vel in binos saltem lobos dividuntur, quamvis eos supra terram foliorum specie non efferant ; et monocotyledones quæ nec folia seminalia bina efferunt nec lobos binos condunt. Hæc divisio ad arbores etiam extendi potest: siquidem palmæ et congeneres hoc respectu eodem modo a reliquis arboribus differunt quo monocotyledones à reliquis herbis." His plan was this : Plants are either Flowerless, or Flowering; and these are Dicotyledones, or Among the genera of Ray, which were what we now call Natural Orders, were Fungi, Mosses, Ferns, Composites, Cichoraceæ, Umbellifers, Papilionaceous plants, Conifers, Labiates, &c., under other names, but with limits not very different from those now assigned to them. 1751. LINNEUS, Charles.-(Philosophia Botanica). "Plantæ omnes utrinque affinitatem monstrant, uti Territorium in mappa geographica." The following is the Natural distribution first proposed by Linnæus, under the name of Fragments. Many of his groups were taken from his predecessors; others were contrived by himself. At a later period they underwent some alteration; but the list He never assigned any chanow given will serve to show the learned author's plan. racters to these Fragments. 1. PIPERITE. Arum, &c. Piper, Phytolacca. 2. PALME. Corypha, &c., Cycas. 3. SCITAMINA. Musa, Canna, Amomum, &c. 4. ORCHIDEE. As now. 24. BICORNES. Azalea, Myrsine, Memecylon, Santalum, &c. 25. SEPIARIE. Jasminum, Ligustrum, Brunfelsia, &c. 5. ENSATE. Iris, &c., Xyris, Eriocaulon, Aphyl- 26. CULMINE. Tilia, Bixa, Dillenia, Clusia, &c. lanthes. 27. VAGINALES. Polygonum, Laurus, &c. 6. TRIFETALOIDEE. Butomus, Alisma, Sagittaria. 28. CORYDALES. Melianthus, Epimedium, Fumaria, 7. DENUDATE. Crocus, &c. & SPATHACE E. Leucoium, Amaryllis, &c. 9. CORONARIE. Ornithogalum, Scilla, &c. 10. LILIACKE. Lilium, Tulipa, &c. 11. MURICATE. 12. COADUNATE. Bromelia, &c. Anona, Magnolia, &c., Thea. 13. CALAMARLE. Scirpus, &c., Juncus ? 14. GRAMINA. As now. 15. CONIFERE. Abies, Pinus, &c. 16. AMENTACE E. Pistacia, Alnus, Populus, Jug-35. SENTICOSE. lans, Quercus, &c. 17. NUCAMENTACEE. Xanthium, Iva, &c. 36. COMOSE. Spiræa, Filipendula, Aruncus. 37. POMACEE. Punica, Pyrus, &c., Ribes. As now. 18. AGGREGATE. Statice, Protea, Hebenstreitia, 38. DRUPACEÆ. Brunia, Valeriana, Boerhaavia, Circa? &c. 39. ARBUSTIVA. Philadelphus, and Myrtleblooms. Cassine, 40. CALYCANTHEME. 19. DUMOSE. Viburnum, Rondeletia, Rhus, Ilex, Callicarpa, Lawsonia, &c. 20. SCABRIDE. Ficus, &c. 21. COMPOSITE. As now, nearly. 22. UMBELLATE. 23. MULTISILIQUE. As now. Modern Crowfoots. Glaux, Rhexia. Enothera, &c., Lythrum, 41. HESPERIDEE. Citrus, Styrax, Garcinia. 43. ASPERIFOLIE. The modern Borageworts. 44. STELLATE. Galium, &c., Hedyotis, Spigelia, 57. SILIQUOSA. Crucifers. Cornus? Coffea, &c. 45. CUCURBITACEÆ. Passiflora and Cucurbits. Sedum, Oxalis, Fagonia, &c. &c. 58. VERTICILLATA. Labiates. 59. PERSONATE. Figworts, Sesamum, Justicia, Bignonia, Verbena, &c. 60. PERFORATE. Hypericum, Cistus, Telephium. 47. TRICOCCA. Cambogia, Euphorbia, &c., Cliffor-61. STATUMINATE. Ulmus, Celtis, Bosea. tia, Sterculia, &c. 62. CANDELARES. Rhizophora, Mimusops, Nyssa. 48. INUNDATÆ. Hippuris, Elatine, Ruppia, Ty- 63. CYмOSE. Lonicera, Loranthus, Ixora, Cinpha, &c. chona? &c. 49. SARMENTACER. Vitis, Hedera, Houstonia, 64. FILICES. As now. 66. ALGE. As now. As now. 50. TRIHILATE. Sapindus, Malpighia, Begonia, 67. FUNGI. 51. PRECIE. Part of modern Primworts. &c. 53. HOLERACEAE.-Spinacia, &c., Herniaria, Callitriche, Petiveria, &c. 54. VEPRECULE. Rhamnus, &c., Lycium, Daphne, &c. 55. PAPILIONACEÆ. As now. All his doubtful genera. At a later period Nos. 7, 10, 11, 17, 26, 27, 36, 38, 39, 60, 61, 62 and 63, were cancelled; and four added, viz. GRUINALES. Cranesbills. Hippophäe, 56. LOMENTACER. Leguminous plants, with HEDERACEA. Hedera and Vitis, &c. jointed pods, Casalpinieæ and Mimoseæ. MISCELLANEЛ. A curious mixture. 1789. JUSSIEU, Antoine Laurent de.-(Genera Plantarum secundum ordines naturales disposita, juxta methodum in horto regio Parisiensi exaratum, anno MDCCLXXIV). Adopting the views of Ray as to primary divisions, Jussieu applied them to the system of Tournefort, which had been in common use in France from the year 1694, and which was by far the best suited for the state of knowledge of the age in which it was promulgated. To this he added the position of the stamens with respect to the ovary, and thus constructed his 15 classes in the following manner : Under each of these classes he arranged his Natural Orders as follows, usually deriv. ing their name from some genus, which he regarded as a good illustration of their general structure. BELE 73. Gerania, 493 74. Malvaceæ, 368 75. Magnolia, 417 76. Anonæ, 420 Class XIV. 83. Sempervivæ, 344 77. Menisperma, 307 84. Saxifragæ, 567 90. Melastoma, 731 96. Euphorbiæ, 274 97. Cucurbitaceæ, 311 98. Urtica, 258 99. Amentace, 248 100. Conifere, 226 1810. BROWN, Robert.—(Prodromus Flora Nova Hollandiæ, &c.) In this work the system of Jussieu is principally followed, but the Classes are omitted, and the sequence of the Orders is changed. The author states that he regards most of the Orders of Jussieu as being truly natural, but his classes, as the latter candidly admits, often artificial, and apparently founded upon doubtful principles. It was the intention of Dr. Brown to publish a second volume of his work, and then to explain his views upon this and other subjects; but that intention has not yet been carried into execution. It is here that we find the importance of the aestivation of the flower pointed out, and applied to the characters of Natural Orders. Those characters have been a model for succeeding writers. 1813. DE CANDOLLE, A. P.-(Théorie Elémentaire de la Botanique, ou Exposition des Principes de la Classification Naturelle et de l'Art de décrire et d'étudier les Végétaux). In this work is to be found the explanation of the principles which guided its clearminded author to the construction of a method of arrangement which has now almost superseded all others, partly because of its easiness and simplicity, and most especially because it is that which has been followed in the author's Prodromus, or celebrated description of species. He himself explains the course he has taken, to the following effect:-"I place Dicotyledons first, because they have the greatest numbers of distinct and separate organs. Then, as I find families where some of these organs become consolidated, and consequently seem to disappear, I refer them to a lower rank. This principle gives me the following series: I have adopted this series partly because I think it that which is least removed from a natural sequence, and partly because it is convenient and easy for study. But let no one imagine that I attach the least importance to it. The true science of general Natural History consists in the study of the symmetry peculiar to each family, and of the relation which these families bear to each other. All the rest is merely a scaffolding, better or worse suited to accomplish that end.”—p. 206, first edition. At this time De Candolle made no attempt to combine the Natural Orders in Alliances; but at a later period (1819), in a second edition of the Théorie, he proposed a few such groups, under the name of Cohorts, as will be seen by the following list of his Orders, taken from the edition of 1819. In that of 1844, published by his son after his death, these Cohorts are all broken up, and considerable alterations are made in the sequence of the Natural Orders. I, however, prefer publishing his plan of forming Alliances, rather than his last list, even although that does give his latest views of affinity. I. VASCULAR OF COTYLE- A. Perianth double; that 6. Berberides, 437 DONOUS PLANTS; that is to say, furnished with cellular tissue and vessels, and whose embryo is provided with one or more cotyledons. 1. Exogens or Dicotyledons; that is to say, where the vessels are arranged in concentric layers, of which the youngest are the outer-, most, and where the embryo has opposite or verticillate cotyledons. is, where the calyx and THALAMIFLORE. on the receptacle. 1. Ranunculaceae, 425 7. Podophylleæ, 430 Cohort II. Carpels soli- 18. Droseraceæ, 433 |