Page:The Botany of the Antarctic Voyage.djvu/271

Falklands, etc.] 1. Pringlea antiscorhdica, Brown, MSS. in Herb. Banks. (Tab. XC.-XCI.)

Radix (seu rhi:oma) prostrata, longe repens, 2-3 pedalis, crassa, diametro 1-2 unc, teres, transverse annulata, sublignosa, sapore Cochlearia Armoracia, pra?cipue versus basin fibras crassas divisas rainosas ernittens, ad apicem foliorum capitulum magnum scaposque 1-2 elongatos gerens. Folia imbrieata, in capitulum, Brassicce oleracetB magnitudine fomiaque, referens disposita, 3-6 unc. longa, latissime obovato-spathulata, basi in petioliun latum attenuate, eamoso-coriacea, concava, margine integenima, ciliata, interdiun pubescentia, intus vasibus oleo subtilissimo repletis percursa. Pedunculi infra folia e rhizomate orti, ascendentes, 2-3-pedales, foKosi, sulcati, crassitie digitis humana?, intus spongiosi, foliis plurimis imbricatis late obovatis sessilibus tecti. Racemus fructiferus elongatus, 6 unc. ad pedalem, e siliculis perplurhrris dense congestis subclavatus. Pedicelli clavati, erecti. Sejxda oblonga, obtusa, dorso pilosa. Petala nulla ! (Anderson MSS.). Stamina parva, filamentis dilatatis. Silicula f— 1 unc. longa?, oblongo-lanceolata?, v. breviter oblonga?, erectse, pubescentes v. patentim pilosa?, pilis simpUcibus, rarius glabra?; valvis coriaceis, dorso convexis, obscure uninerviis ; replo gracili, persistente ; placentis biserialibus, e dissepimento retracto fungosis. Semina perplurima, majuscula, 1 lin. longa, subimbricata, e funiculo valido arcuato pendula, ovato-cordata, subcompressa, deorsum in rostnun breve obtusum producta ; testa crassa, spongiosa, albida ; cotyledonibus acciunbentibus, radieula mediocri a?quilonga.

This is perhaps the most interesting plant procured during the whole of the voyage performed in the Antarctic Seas, growing as it does upon an island the remotest of any from a continent, and yielding, besides this esculent, only seventeen other flowering plants.

I am unable to point out any very close affinity which this curious genus may have with others of the same natural family, and shall therefore confine myself to enumerating its peculiarities, and how far these may be common to others of the order to which it belongs. The long stout rhizoma is very similar to the root of the Coclrfearia Armoracia (Horse-radish), and not altogether different from that of the common kail or cabbage, which is however an annual plant, whilst the root-stocks of Pringlea and of the Horse-radish are perennial. In the forrn of the head of leaves, the resemblance to the common cabbage {Brassica oleracea) is most striking, and so is the use both are put to; but this analogy cannot be carried further ; our garden escident bears its flowers on a branching stem, that rises from amongst the leaves and is a continuation of the axis of growth of the plant, and it is chiefly owing to a check in the development of the parts connected with the inflorescence, or a complete suppression of those parts, that the annual leaves are increased in number and assume the densely capitate fonn ; here, on the other hand, the annual flower-stalks spring invariably from the base of the cluster of perennial leaves and are wholly independant of them, as occurs in the horse-radish, in various Drabas, in Arabk Macloviana, and in some other perennial Crucifera more frequently inhabitants of cold climates. But it is in the parts of the inflorescence that the most important botanical characters reside, and by them the position of this plant must be determined in the natural series. The flowers though carefully sought, escaped my observation, owing to the lateness of the season of our arrival. Broken sepals and small stamens, with short dilated filaments and oblong-lanceolate anthers, of a dark colour, were all I coidd detect; the stigma is peltate and quite entire.

The silicula accords in fonn with that of several Ali/ssinea, to which group in De Candolle's arrangement Pringlea must be referred. There is no marked difference, except size, between the valves in this genus and Cochlearia the septum, wholly absent here, is fenestrate in C.fenestrata, Br., a native of Arctic America, whilst the clavate peduncle, short style and broad peltate stigma, are very characteristic of other species of that genus. The presence or absence of a dissepiment, at all times spurious in the order, and of which there is a partial suppression in a genus usually provided with a complete one, cannot be considered a character of the greatest importance though very conspicuous ; nor do we in any case find its absence in Crucifera with the more ordinary structure of seed-vessels to indicate any affinity between the plants thus characterized. In Cochlearia the septum is easily separable into the two, plates of which it is composed, as observed by Brown, and close to the septum the origins of these plates are remote, so