is. According to my observations, it is neither unfrcquent, nor always of generic importance. Thus, I find it to exist in some species only of Arabis namely A. Turrita, peudula, and canadensis, and hence I did not introduce it into my generic character of Parrya, though I have noticed it in my description of the species. The principal difference existing between these two species of Koniga is that the cells of the ovarium and silicula of K. maritima are monospermous, while those of tibyca are polyspcrmous, the number being variable, apparently indefinite, but not exceeding six. There are, however, other instances in this family, in which the mere difference between definite and indefinite number of seeds is of specific importance only, as in Draba and Meniocus, in each of which a species exists with dispermous cells; and the objection arising from the apparently still greater difference between unity and indefinite number in the two species of Koniga is removed by a supposed third species or variety of K. maritima, in which two seeds are occasionally produced in each cell. It may even be observed, that from unity to the indefinite number in this case, where the ovula in the different cells are alternate, the transition is perhaps more easy than from the binary to the indefinite, in cases where, as in Alyssum properly so called, the ovula are placed opposite in the different cells, and are in the same cell equidistant from its apex ; this symmetry, probably, admitting of addition only by fours. The next genus of Cruciferse to be noticed is F a r s e t ia , a fragment of the original species of which is in the collection. There are also several specimens of a plant, found in the desert, supposed to be new, and which, though without flowers, and considerably different in the form of its stigma, I am inclined, from the resemblance in habit, in pubescence, in silicula, in seeds, and especially from the exact similarity in the structure of the septum, to refer to the same genus *. * FARSETIA. Farsetia. Turra Farsetia, p. 0. Farsetise sp. ffort. Ketu. ed. 2. vol. 4. p. 69 De Cand Syst. 2. p. 286. C h a r. Gen. Calyx clausus, basi v ix bisaccatus. Filament a omnia edentula. Anthcrm lineares. Si/icula ovalis v. oblonga, sessilis, valvis planiusculis, locuiis polyspermis (raro 1-2- spenxus), fumculis liberis. Dmepimentum uninerve, venosum. Semina mnrginatu. Cotyledones accumbentes. Herb« sujfrnticosee ramos<r,pube bipartita appressa incance. Folia integerrima. Racemi subspicati. As the introduction of the structure of the dissepiment into the generic characters of Cruciferm is now proposed for the first, time, and as I believe that its texture and nppcuranco should always be attended to in constituting genera in this family of plants, I shall here offer a few remarks respecting it. According to the particular view which I briefly but distinctly published in 1818, and which M. de Candolle first adopted in 1821, of the composition of the pistillum in Cruciferæ*, the dissepiment in this family is necessarily Obs. Dissepimentum in omnibus exemplaribus utriusque speciei a nobis visis completum, scd in F. ægyptiaca quandoque basi fenestratum, fide D. Desfbntaines. ( Flor. Allant. 2. tab. 160.). F. ægyptiaca species unica certa est, nam F. stylosa, cujus flores ignoti, ob stigmatis lobos patentes non absque hæsitatione ad hoc genus retuli. F a r s e t ia ? stylosa, ramosissima, siliculis oblongis polyspermis passimquè brevô ovalibus 1-2-spermis, stylo diametrum transversum siliculæ suboequante, stigmatis lobis patentibus. Obs. Exemplaria omnia foliis dcstituta, sed illorum cicatrices ni fallor obvioe. * In a work published in 1810, the following passage, which has some relation to this subject, occurs. “ Capsulas omnes pluriloculares e totidem. thecis confer rum inutas esse, diverses solum modis gradibusque variis côhæsionis et solubilitatis partium judico.”—(Prodr. Flor. Nov. Hoil. 1. p. 558.) This opinion, however, respecting the formation of multilocular ovaria, might be held, without necessarily; leading to the theory in question of the composition of the fruit in Cruciferse, which I first distinctly stated in an Essay on Compositæ, read before the Linnean Society in February 1816, and printed in the 12th volume of their Transactions, published in 1818. In this volume (p. 89), I observe that <c I consider the pistillum of all phænogamous plants to be formed on the same plan, of which a polyspermous legumen, or folliculus, whose seeds are disposed in a double series, may be taken as the type. A circular series of these pistilla disposed round an imaginary axis, and whose number corresponds with that of the calyx or corolla, enters into my notion of a flower complete in all its parts. But from this type, and number of pistilla, many deviations take place, arising either from the abstraction of part of the complete series of organs, from their confluence, or from both these causes united, with consequent abortions and obliterations of parts in almost 'every degree. According to this hypothesis, the ovarium of a syngenesious plant is composed of two confluent ovaria, a structure in some degree indicated externally by the division of the style, and internally by the two cords (previously described), which I consider as occupying the place of two parietal placent«, each of these being made up of two confluent chordulæ, belonging to different parts of the compound organ.” In endeavouring to support this hypothesis by referring to certain natural families, in which degradations, as I have termed them, are found/from the assumed perfect pistillum to a structure equally simple with that of Compositæ, and after noticing those occurring in Goodenoviæ, I add, M The natural order Cruciferse exhibits also obliterations more obviously analogous to those assumed as taking place in syngenesious plants ; namely, from a bilocular ovarium with two f f ■ ■ ■ ■
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