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nhat of Linnæus middle of last centlasses, many ofrolla as
Giders, because it affords marks, which are subject to little Variation.
Tournefort, whose system was more followed than any other, except that of Linnæus, particularly in France, and even in this country, till after the middle of last century, fixed on the form of the corolla for the foundation of his classes, many of which were very natural: but the great variety of forms the corolla assumes, many of which approach each other so nearly, as scarcely to be distinguished, render the application of his system to practice difficult.
Many systems, both artificial and natural, have been devised by different botanists, * all of which gave way to the artificial system of Linnæus, termed sexual, because the distinguishing marks of all his classes are taken from the parts of generation, i. e. the pistillum and stamina...
The Linnæan method owes its success, not only to the suped rior facility, as well as. certainty, by which any plant, by means of it, may be reduced to its class and order; but to the attention the author has paid to the more minute divisions, and to the pains he has taken to give accurate descriptions of the species, and to affix to each its trivial name. The different publications of Linnæus, particularly his System of Nature, and Species Plantarum, have done more for the advancement of botanical knowledge, than the writings of any other man. Since the time his last supplement was published, a very great number of species have been discovered in different quarters of the world. Those which have been described, are dispersed through the writings of various authors; others are only to be met with in the herbarie of the curious. Linnæus junior, in his supplement, has described several: Murray and Gmelin, in their editions of the System of Nature, have published only such as they themselves had an opportunity of examining, together with those described by Thunberg and Jacquin.
, It was long the earnest wish of those who were occupied with such studies, that some person, properly qualified, would give them in a collected form to the world, Willdenow undertook the Herculean labour; and from the manner in which he has conducted this edition of the Species Plantarum, has shewn himself well qualified for the task. He has adopted none of the alterations in the classes, proposed by the vol. X. NO. 20.
* Adanson, a Frenchman, to show the facilitỳ with which they may be formed, and his own dexterity, has manufactured upwards of fixty of them,
authors we shall mention below; but has, with two exceptions, adhered very closely to the arrangement of Linnæus, at least in the larger divisions. · Notwithstanding the merits of the Linnæan system, it has. without doubt many imperfections, which different botanists have endeavoured to correct, but hitherto without any very distinguished success. The two principal objections are, 1st, that plants, evidently connected by nature, are, according to it, place ed in different classes, and that those which have no natural or general affinity, are sometimes arranged under the same class, an objection to which every artificial system must be liable. 2dly, Plants, by means of it, cannot always be ascertained with such facility and precision as might have been expected in an artificial arrangement. The improvements which have been aimed at, have been suggested principally with a view to make the arrangement more natural; and indeed, Linnæus's own anxiety to remedy its defects in this particular, is one cause of the difficulty which is frequently experienced in reducing a plant to its proper place. In the class Diadelphia, for example, which ought to contain those plants whose stamina are united, by means of their filaments, into two groups, there is a subdivision in the order Decandria, containing a number of genera, characterized Omnia stamina connexa ; though it is obvious, that any one who knows merely the general principle of the Linnæan arrangement, would naturally look for such a flower in the class Monadelphia. · Had Linnæus, instead of making this exception, improved the definition of his class by means of the form of the flowers, he would not only have obviated this difficulty, but rendered the class itself more natural, and made it comprehend those irregular members of the family which have their stamina unconnected. For there are many plants standing in the order Monogynia, of the class Decandria, which, from the form of their flower, and nature of their seed-pod, evidently belong to the class Diadeler phia. ,
Any alterations, therefore, made with a view to render the arrangement more natural, which have a tendency to make it more complex, are certainly improper. Instead of depriving an artificial system of its principal recommendation, by patching or twisting it, it would be better, at once, to have recourse to natural classes, such as have been formed by Linnæus himself, by Batsch or Jussieu. But if an artificial arrangement be thought best adapted to the present state of botanical knowledge, such alterations only should be made, as tend to remove ambia guity and difficulty. Of all the alterations and attempts to improve the Linnæan system, there are but few that merit notice. Liljebad has made the following changes. He joined the 7th, 8th and 9th, to the 10th class ; the 11th to the 13th ; and the 18th, 21st, 22d and 23d, he included in one, and thus reduced the number of classes to 16. He has had few followers; there: fore, we shall not stop to point out the impropriety of some of these combinations.
Thunberg has reduced the number to twenty, by distributing the plants of the 20th, 21st, 22d and 23d classes, among those classes to which they are referable, according to the number and connexion of the stamina. His reasons for abolishing the classes Monoecia, Dioecia and Polygamia, are, 1st, The plants which belong to them are not always constant in point of sex; for culture, and a difference of climate, frequently removes a plant from the Monoecia, or Diccia, to the Polygamia. 2dly, By ara ranging the genera which compose these classes according to the nature and connexion of their stamina, mary of them will štand in the same class with others which they resemble in al. most every particular, except in the circumstance of having their male and female organs placed in separate flowers, either on the same or on different plants. His reasons for abolishing the class Gynandria are not equally valid:
Gmelin, in addition to the alterations proposed by Thunberg, which he has adopted in his edition of the Syst. Nat., has likewise united the class Icosandria to Polygamia, and consequently reduced the number to nineteen. This union is certainly unne cessary, if not altogether improper, as these two classes are sufficiently distinguished by the insertion of their stamina ; a distinction which he himself has retained in his subdivisions of the united classes.
Willdenow, we think, has done right in rejecting all these proposed reductions in the number of classes; for it rarely happens that any considerable alteration can be made in a long established system, without producing some confusion and inconvenience ; therefore none ought to be made or adopted, but such as evidently tend to produce some very considerable improvements, which is not the case with any of those hitherto made on the sexual system. The only deviations he has made from the arrangement of Linnæus, are, first, to break up the order Monogynia, of the class Syngynesia, and to place the plants which composed it, according to the number of the stamina, without any regard to their connexion by the antheræ. The plants belonging to this order, certainly have no affinity to the others which compose the class Syngynesia, which becomes a perfectly natural assemblage after their removal. Secondly, He has removed a great number
merous, and speciertant, therents madak, with and to theation of the
of genera from the class Gynandria, and arranged them according to the number and connexion of their stamina. This class should comprehend those plants only whose stamina are attached to the pistillum; but Linnæus has introduced some whose stamina stand under the germen, attached to an elongation of the peduncle, which rises above the receptacle ; and to the admission of these Willdenow objects, we think, with good reason. . . Although the improvements made on the arrangement of Linnæus be unimportant, the changes among, and additions to, his genera and species, by Willdenow and others, have been very numerous. How far, in every instance, he has acted properly or otherwise, in making and adopting these, cannot be determined by any one who has not had access to the same sources of information as Willdenow himself, and who has not bestowed the same attention. From a pretty full examination of his volumi. nous work, however, we are disposed to rate his abilities as a botanist very high, and to place much confidence in his accuracy. His Species Plantarum, we are confident, will be highly prized by those who are best able to appreciate its merits. He has described a considerable number of species himself, and corrected such descriptions of former species as appeared to him not sufficiently accurate.
We have compared some of these corrections, made on the descriptions of species with which we are acquainted, and find they render the diagnosis more complete. He always mentions in what state he had seen the plants from which he has taken his descriptions ; whether from a living plant or from a dried specimen; from one in flower; in fruit, or otherwise : so that an opinion may be formed how far the accuracy of his descriptions may be depended on. He likewise quotes his authority for every thing he has taken from others.
To give some idea of the great additions and many changes that have been made since the time of Linnæus, we shall now mention the number of the genera and species which have been added to the different classes, and notice the changes that have been made in each.
Genera added to the class MONANDRIA, viz.
Monogynia-Hellenia 4 species, Hornstedtia 2, Hedychium 1; Phrynium 1, the Pontideria Ovata of Linnæus ; Lopezia 1, Phylydrum 1, Cucularia 1, Qualia 2, Usteria 1, Pollichia 1, Mithridatea l. · Digynia-Lacistema 1.
28 Species of former genera have been added to this class, 16 of which have been described by Wildenow, viz. Amomum 8, 7 of which are described by Willdenow. Costus 2. Alpinia 2, i described by W. Maranta 2, both by W. Thalia 1. Boerhavia 6, 4 by W. Salicornia 5, 2 by W. Callitriche 1.
Genera added to the class DIANDRIA. " · Monogynia-Pimelia, 4. species, composed of Passerina Gnidia, P. pilosa, and P. prostrata of Linnæus. Gallipea 1, Wulfenia 1, Cyrtandria 2, Boea 1, Ghinia 2, Sciuris 1, Fontanesia 1, Lithophila 1, Linociera 1, Aruna 1.
Digynia-Crypsis 1, the Anthoxanthum aculeatum Lin. suppl. Schoenus aculeatus of the Spec. Plant. · 172 Species of former genera have been added to this class, 44 of which are described by Willdenow, viz.
Monogynia-Jasminum 9, 2 by W. Ligustrum 1. Olea 2, Chionanthus 3, 1 by W. Syringa 2, 1 by W. Veronica 17, 7 by W. Pæderota 1. Justicia 57, 10 by W. Gratiola 6, 3 by W. Calceolaria 5. Pinguicula 1, and by W. Utricularia 2, both by W. Verbena 4, 2 by W. Cunila 1, and by W. Monarda 2. Rosmarina 1. Salvia 26, 8 by W. Collonsonia 1. Ancistrum 1. Anthoxanthum 1.
Digynia --Piper 29, 6 by W..
Monogynia--Aristea 1, the Ixia Africana of Linnæus. Witsenia 1, the Antholyza Maura of Lin. Marica 1, Xiphidium 2, Oxylaphus 1, Macrolobium 3, Rohria 1, Tonsella 2, Fissilia 1,
Digynia" Miegia 1. Obium 3, Rol
Digynia--Mecklenbergia 1. Perotis 2, 1 of them the Saccharum Spicatum of Lin. Lursia 4, of which the Phallaris Orizoides of Lin, is 1. Pappophorum 1. Lappago 1, the Cenhrus Racemosus of Lin.
Trigynia--Doriatia 1, the Polycarpon Magellanicum of Lin.
423 Species of foriner genera added to this class, 105 of which have beer described by Willdenow.
Monogynia----Valeriana 6. Comocladia 1, and by W. Polycnemum 1, 3 by W. Crocus 1, and by W. Hyppocratea 2, 1 by W. Ixia 22, 9 by W. Gladiolus 28, 14 by W. Antholyzá... Iris 16, 6 by W. Moræa 5, 2 by W. Wachendorfia 2. Commelina 3, 2 by W. Xyris 3, 1 by W. Kyllengia 4, I by W, Shoenus 26, 3 by W. . Cyperus 47, 15 by W. Scirpus 32, i by W. Eriophorum 1. Cenhrus. 3. .
Dirymia--Saccharum 6, 2 by W. Phalaris 3. Paspalum 9, 2 by W. Panicum 44, 7 by W. Phleum I. Alopecurus 3. Millain 5. Agrostis 20, 7 by W. Aira 5, 1 by W. Melica 6. Pox 33, 10 by W. Briza 1. Dactylis 10, 3 by W. Cynosurus 10, i by W., Festuca ll, I by W. Bromus 9, 1 by W. Stipa 3. Arena 12, 2 by W. Arundo 5. Aristidia 3. Lolium 1, and by W. Rottboellia 10, 4 by W. Elymus 2, 1 by W. Hordeum 2. Triticum 3.