Original Articles. SUR UNE NOUVELLE ESPÈCE DE SHEARERIA. PAR M. A. FRANCHET. (TAB. 198). SHEARERIA POLII, n. sp. Annua, erecta, semi- vel vix pedalis, glabra; ramuli graciles, patentes vel arcuato erecti; folia alterna, sessilia, inferne longe attenuata, oblonga vel obovato-spathulata, obtusa vel etiam apice subemarginata, nervo excurrente mucronulata; capitula ad apicem ramulorum solitaria, basi nuda vel sæpius folio supremo contiguo bracteata, subsexflora; foliola involucri 5-6, subbiseriata, interioribus vix longioribus, ovato-lanceolata, margine pallidiori membranaceo subtiliter erosula et papillis ciliata, dorso distincte nervata; flores radii 3, feminei, fertiles, ligulati, ligulâ (pallide purpurascenti ?) obovatâ, apice vix distincte emarginatâ ; flores disci bisexuales, circiter 2-3, steriles, lutei, tubulosi, profunde 5-lobati, lobis lanceolatis acutis, margine tenuiter papillosis, cæterum glabri, floribus radii duplo breviores; stylus in fl. disc. et rad. bifidus, ramis lanceolato-cylindricis, subacutis; achanium (juvenile) oblongum, inferne attenuatum, apice rotundatum, compressum, obscure 3-4-gonum, angulis membranaceis serie papillarum ciliatis. A Sheareria nana, S. Moore, præcipue differt: foliis omnibus evolutis oblongo-spathulatis nec linearibus, squamæformibus; achæniis oblongis, nec e basi latiore apice angustatis; glabritie. Nous n'avons pas vu les achanes murs de cette espèce. Dans leur jeune âge ils sont trés comprimés et leurs angles sont surtout indiqués par une ligne de papilles d'un jaune d'or; dans toutes les fleurs le style est bifide, tandis que M. S. Moore dit que chez le S. nana le style des fleurs du disque est entier. Autant que nous en pouvons juger sur le sec les ligules du S. Polii sont rosées ou d'un pourpre pâle; les capitules campanulés ne dépassent pas 4 mill. et les feuilles 15 à 20 mill. de longueur. Cette espèce a été récoltée à Mé-chi, partie N. O. du TchéKiang, Chine, le 27 Sept., 1876, par M. Henri de Poli. DESCRIPTION OF TAB. 198.- Sheareria Polii, Franch. (nat. size). - Fig. 1. Flower of the disk. Fig. 2. Style of disk-flower. Fig. 3. Flower of the ray. Fig. 4. Style of ray-flower. Fig. 5. Very young achene. Fig. 6. Scale of the involucre. (Figs. 1 to 6 much enlarged). N. S. VOL. 7. [SEPTEMBER, 1878.] 2 L ON THE PLACE OF CHARACEÆ IN BY PROF. T. CARUEL. MR. BENNETT has discussed this subject in an interesting paper which appeared in the Journal of Botany' for July (p. 202), condensing in a few pages most of what has been written on the structure and affinities of Characea. He has incidentally mentioned the place I have given them, as forming a separate division (or primary group) beetween Phanerogams and Prothallogams; but as he has not recorded my reasons for so doing, perhaps some explanation on my part will not come amiss. In my recent book on Morphology* I have tried to bring into full light the fact that all vegetable organisms (except the very lowest) are represented in every species by three different forms, in alternating generations, viz., a neutral form, producing, either directly or indirectly, two sexual forms, which by their action on each other reproduce the neutral form. Now these present different and even opposite characters, according to the various series of plants; and of such I have availed myself to define better those large primary divisions of the vegetable kingdom that, under different names, are now admitted by all botanists. In Bryogams (Mosses), and those Gymnogams that are trimorphous (such as Oedogoniacea), the female form is indefinite in its evolution, and organized so as to produce in succession a long series of archegonia and thence embryos (or of oogonia), and of antheridia, which last produce the phytozoa or male form; while the neutral form is, on the contrary, definite in its evolution, in Mosses beginning as an embryo, and terminating shortly by the formation of the urn at one end. In the remainder of the vegetable world the process is reversed: it is the neutral form that is indefinite, while the female forms (gemmule in Phanerogams, prothallus in Ferns and their allies) are definite, only once producing the embryo of the neutral form. And such is the case with Characea, which can therefore by no means be brought together either with Mosses or with Alga. Much stress has been laid on the supposed similarity between Characea and Mosses, from the circumstance that these last, when they are cormophytes, begin by a filamentous thallus, on which subsequently buds are formed; and Characea have been deemed to act likewise. But notwithstanding the high authority of those who support this view of the case, I own I cannot side with them. A careful examination of the process of germination in Characea, as exposed by Pringsheim and De Bary, shows indeed the lateral formation of buds on a previous simple shoot; but as this contemporaneously gives out leaves on the other side, it can be considered in no other light than as a stem, and nowise as homologous with the thallus (protonema) of Mosses, however it may resemble it in general appearance. On comparing Characea with Prothallogams, we find a resemblance in the structure of the phytozoa, and in the main points of the process of germination, in both the neutral plant originating crosswise and directly from the top of the embryo or of the oospore. But there is a wide difference in the total absence of anything like the sexual prothallus so peculiar to the Prothallogams, as also in the complex organisation of the antherocyst compared to the simpler antheridium, and of the oogemma compared to the archegonium, and in the very different origin of both, which in Characea proceed directly from the neutral form and not from spores produced by it; on the other hand, comparing them with Phanerogams, we find a marked resemblance of structure, coupled with the same origin, between the oogemma of the one and the gemmule (misnamed ovule) of the other; and I perfectly agree with Celakovsky in considering them homologous organisms. There is, moreover, a similarity of origin in the male forms of both the groups, equally proceeding from bodies which are modifications of leaves. But alongside with these analogies we have such differences in the structure of the male apparatus, and in the process of formation of the neutral plant, which in Phanerogams begins as an embryo placed lengthwise at the end of a proembryo, that there is no need to insist on the necessity of separating Characea from Phanerogams as well as from Prothallogams. Then what remains to be done with them, except to recognize simply that they have a right to stand by themselves as a distinct group, equal in rank to the four others generally admitted? Sachs was the first to think so, and I am sorry to see he has altered his opinion, on grounds quite insufficient, as Mr. Bennett has well shown. As a distinct group, the position of my Schistogams can be nowhere but between Phanerogams and Prothallogams, in a morphological system of classification, such as ours all essentially are. One last word on a more general subject. As none of the primary groups that I have admitted in my classification-Phanerogams, Schistogams, Prothallogams, Bryogams, Gymnogams-are of my own making, it may be deemed superfluous, or even worse, for me to have given them new names (except the first one). I have been led to do so by the following considerations :-Firstly, in order to put forth more strongly the idea, which now-a-days will be disputed by very few, that the old class Cryptogamia of Linneus must be split up into a number of groups, each fully equivalent to the Phanerogams. Secondly, to do away, for these groups, with such names as Vascular Cryptogams and Cellular Cryptogams, which imply that they are subdivisions of some superior group. I really believe it would be a gain for science to let fall altogether the term Cryptogams, which in the present state of botany has nothing left it but a negative signification. Ir has recently been my misfortune to collate several catalogues of plants for the purpose of comparing the vegetation of the countries to which they refer. One cannot engage in such an undertaking without being painfully impressed by the confusion which exists in botanical nomenclature and in the practice of citing authorities, and of the necessity for a reform in both particulars. I venture therefore to say a few words upon a question which has lately been discussed in the pages of this Journal. The authority which is attached to the name of an organic form may be regarded from one of two points of view-1st, as referring to the collocation of the two members of the double name, i. e., of the left hand or generic, and of the right hand or specific member; 2ndly, as referring to the right hand or specific member only. The former practice has hitherto prevailed among botanists, the latter among zoologists. There is no à priori reason in the nature of things why the one convention is preferable to the other. It is simply a matter of convenience, and the question is, on which side does the balance of convenience lie? It is evident that there ought not to be two rules, the one for the vegetable, the other for the animal kingdom. It follows from the second or zoological rule that the oldest specific name has the right of priority, and that it carries with it the initials of the author, however various the genera in which the organism may have been placed by the vagaries of subsequent describers. An exception may of course arise if the oldest specific name has a manifest impropriety in a new connection. 66 If the botanists who speak of this as a new rule" will refer to a catalogue of shells, they will find the old Linnæan genus Venus now subdivided into many genera, one of which is Cyprina of Lamarck; but they will see the old Venus islandica of Linnæus · described as Cyprina islandica, LINN., not Cyprina islandica, LAM. (Forbes & Hanley, British Mollusca,' vol. i. p. 441). Or take a catalogue of insects (I have before me both editions of Staudinger's 'Lepidoptera of Europe'), and turn to the old Linnæan genus Papilio. The Peacock Butterfly, now placed in the genus Vanessa of Fabricius, stands as Vanessa Io, LINN., not Vanessa Io, FAB.; and so on to the end of the chapter. A difficulty arises when an author makes an existing specific name the name of a new genus. Thus Fabricius changes the name of the Goat Moth, Bombya Cossus, Linn., into Cossus ligniperda. In the first edition of his Catalogue' (1861) Staudinger gives Cossus ligniperda, Fab., but in the second (1871) he boldly reduplicates the earliest specific name, and writes Cossus Cossus, Linn. The zoological rule has great advantages. It saves us from a host of useless authorities, and worse than useless synonyms; it ensures that the name of the first describer shall generally, if not invariably, be associated with that of the organism; and it removes from vain and shallow authors the temptation to hand their names down to posterity as a reward for confusing the nomenclature. Indeed, so well has the rule worked in Entomology that insects may be, and frequently are, referred to, in conversation, by their specific names only. Let us now examine the working of the other rule in the vegetable kingdom. The first point to be noticed is that botanists often disagree as to what authority to attach to any given combination. The genus Erodium was founded by l'Héritier on a section of the Linnæan genus Geranium. If we search for the authority for Erodium moschatum, formerly Geranium moschatum, Linn., we find the following remarkable differences of opinion : Erodium moschatum, L'Hérit. in Ait. Hort. Kew. (Koch; Nyman, Erodium moschatum, Ait. (Reichenbach). Erodium moschatum, Smith. (Bab. Man., ed. 7.) Here we have at least three different designations of the same plant, in a case where a zoologist would have written Erodium moschatum, Linn., as a matter of course, and given himself no further trouble.* It is scarcely necessary to point out how misleading this is. "Erodium moschatum, L'Hérit.," "Erodium moschatum, Willd.," and "Erodium moschatum, Smith," ought, according to all analogy, to stand for three different plants, and not for three different views of the authority for one. A still more serious mischief than the confusion of authorities is the liberty which botanists have accorded to themselves, in moving a well-known plant into a new genus, of changing its specific name, and the frightful multiplication of synonyms of which this has been the cause. According to some of the correspondents of this Journal we ought to be grateful, rather than otherwise, for this exercise of the fancy. The common Male Fern, Polypodium Filix-mas of Linnæus, has been placed in at least eight different genera, and received two specific names besides the first. It is a matter of accident rather than design that this plant has not as many specific names as generic, with sixty-four combinations of the two, and a different authority for each combination. The nomenclature of Orchids is nearly as bad as that of Ferns. The common Frog Orchis stands in seven genera, but has happily only one specific name. With Neotinea intacta we are not so fortunate this plant is an admirable instance of the logical * On the correct authority for Erodium moschatum see a note at p. 282.— [ED. JOURN. BOT.] |