present, however, inclined to adopt the^subdivision of both these genera, as proposed by several authors, and received by M, De Candolle j but to this subdivision the author pf the Systema Naturale must have been determined on other grounds than those referred to ; for in these four genera, in which the three principal modifications of cotyledons occur, he has taken their uniformity for granted. As to the place of Savignya in the natural family, I believe, on considering the whole of its structure and habit, that it ought to be removed from Alys- sineas to a subdivision of the order that may be called Brassiqece, but which is much more extensive than the tribe so named by M. De Candolle ; including all the genera at present known with conduplicate cotyledons, as well as some others, in which these parts are differently modified. There are two points in the structure of Savignya, that deserve particular notice. I have described the asstivation of the calyx as valvula,r; a mode not before remarked in this family, though existing also in Ricotia. In the latter genus, however, the apices of the sepals are perhaps slightly , imbricate, which I cannot perceive them to be in Savignya. The radicle is described by M. De Candolle as superior* with relation to the cotyledons. I am not sure that this is the best manner of expressing the fact of its being horizontal, or exactly centrifugal, the cotyledons having the same direction. This position of the seed is acquired only after fecundation; for at an earlier period the foramen of the testa, the point infallibly indicating the place of the future radicle, is ascendant. From the horizontal position of the radicle in this and some other genera, especially Farsetia, we may readily pass to its direction in Biscutella, where I have termed it descendant; a character which I introduced to distinguish that genus from Cremolobus. But in Biscutella the embryo, with reference'to its usual direction in the family, is not really inverted, the radicle being still placed above the umbilicus. On the contrary, in Cremolobece, a natural tribe belonging to South America,- and consisting of Cremolobus and Menonvillea, though the embryo at first sight seems to agree in direction with the order generally, both radicle and cotyledons being ascendant, it is, in the same sense, not only inverted, but the seed must also be considered as resupinate: for the radicle is seated below the umbilicus, and also dccupies the inner side of the seed, or that next the placenta,—peculiarities which, taken together, constitute the character of the tribe here proposed. It appears to me singular that M. De Candolle, while he describes the embryo of these two genera as having the usual ^structure of the order, should consider that of Iberis, in which I can find no peculiarity, dèviàiting from that structure *. L u n a r i a l i b y c a of Viviani f is the second.plant of Crùcïfer&, on which I have some observations to offer. This species was described and figured, by the author here quoted, in 1824, from specimens 'collected in 1817 by Della Celia. The specimens in the herbarium were found near Tripoli, where the plant had also been observed in 1819 by Mr. Ritchie, who referred it to Lunaria, and remarked that thé calyx was persistent. Professor Sprengel, in his Systema YegetabiliUm, considers it a species of Farsetia. That this plant ought not to be associated either with the original species of Lunaria, or with Savignya, as now constituted, is sufficiently evident. And if it is to be included in Farsetia, it can only be on the grounds of its having a Sessile silicule, with compressed valves, an indefinite number of Sëeds in ëâch cell, and accumbent cotylédons. But in these respects it accords equally with Meniocus, a genus proposed by M. Desvaux, and with some hesitation received by M. De Candolle, and with Schivereckia of Andrzejowski, which he haS also adopted. I t does not, however, agree with either of those genera in habit, and it is easily distinguished from both by its simple filaments and other * SAVIGNYA. Savignya. De Cand. Syst. 2. p. 283. Lunariæ sp. DeUle. Desvaux. Viviani. C h a r. Gen. Calyx basi æqualis ; æstivatione valvata. Silicula oblonga, septo conformi, valvis convexiusculis. Semina biseriata imbricata marginata. Cotyledones conduplicatæ. Herba annua, glabra (quandoque pube rara simpltci). Folia crassiuscula, inferiora obovaia in petiolum attenuata grosse dentata, media soepe incisa, superiora linenria. Raceml Oppositifolii, ebracteati. Flores parvi erecti, pctalis violaceis venis saturatioribus. Siliculee racemoses, divaricates, itiferiores sespius deflexes. Calyx erectus, æstivatione valvata, ipsis apicibus vix imbricatis. Pelala unguiculata, laminis obovatis sub æstivatione mutuo imbricatis. Stamina distincta, edentula, singulum par longiorum. glandula subquadrata extus stipatum ; breviora, quantum e speciminibus observare licuit, eglan- dulosa. Ovariutn brevissime pedicellatum, ovulis adscendentibus nec horizontalibus. Stylus brevis. Stigma capitatum ■ vix bilobum. Silicula breviter manifeste tamen stipitata, oblonga nunc oblongo-elliptica. Valvules uninerviæ reticulato-venosæ. Dissepimentum e lamcllis duabus sepa-* rabilibus uninerviis venis anastomozantibus obsolctis : areolis subtransversim angustato-linearibus, parictibus ( tubulis ) rectis subparallelis- Funiculi horizontales, dimidio inferiore septo arete adnato superiore libero. •j* Flof. Lib. Specim, p. 34* tab. 1 Q.f. I.
27f 24
To see the actual publication please follow the link above