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Show 858 CUCUil.BITACEOUS PLANTS. CllAl'. X. presque comparable i1 cello des ospcces los mieux caractcrisces." Ono variety, l'Orangin (pp. 4.3, 63), has such prepotency in transmitting its cl111ractcr that when crossed with other varieties a Yast majority of tho seedlings como true. Nauilin, referring (p. 4.7) to G. pepo, says that its l'UCOS "no different des CSpCCCS veritables qu'on CO qu'ellcs pouvent s'allior los uncs aux autrcs par voio d'hybriilitc, sans quo lom· descendance pcrde la facultC de so perpetuor." If wo were to trust to exter~al differences alone, and give up tho test of sterility, a multitude of spocws would have to be formed out of tho varieties of these throe species of Cucurbita. Many naturalists at the present day lay far too little stress, in my opinion, on the test of sterility ; yet it is not improbable that distinct species of plants after a long course of cultivation and variation may have their mutual sterility eliminated, as we have every reason to believe bas occuncd with domesticated animals. Nor, in the case of plants under cultivation, should wo be justified in assUllling that varieties never acquire a slight degree of mutual sterility, as we shall more fully see in a futuro chapter when certain facts arc given on tho high authority of Gartner and Koll'cutcr. 138 The forms of G. pepo are classed by Nauilin under seven sections, each including subordinate varieties. lie considers this plant as probably the most variable in tho world. The fruit of one variety (pp. 33, 46) exceeds in volume that of another by more than two thousand fold ! When tho fruit is of very largo size, tho number produced is few (p. 45); when of small size, many arc produced. No loss astonishing (p. 33) is the variation in tho shape of tho fruit; the typical form apparently is egg-like, but this becomes either drawn out into a cylinder, or shortened into a flat disc. We have also an almost infinite iliversity in tho colour and state of surface of the fruit, in tho hardness both of tho shell and of the flesh, and in the taste of tho flesh, which is either extremely sweet, farinaceous, or slightly bitter. Tho seeds also differ in a slight degree in shape, and wonderfully in size (p. 31), namely, from six or seven to more than twenty-five millimctrcs in length. In tho varieties which grow upright or do not run and climb, the tendrils, though useless (p. 31), arc either present or are represented by various semi-monstrous organs, or are quito absent. The tendrils arc oven absent in some running varieties in which tho stems arc much elongated. It is a singular fact that (p. 31), in all tho varieties with dwarfed stems, tho leaves closely resemble each other in shape. Those naturalists who believe in tho immutability of species often maintain that, oven in tho most variable forms, the characters which they consider of specific value are unchangeable. To give an example from a conscientious writor,l39 who, relying on tho labom·s of M. Naudin and 1:!8 Gii.rtncr, 'Bnstardorzeugung,' 184D, s. 87, and s. 16!) with respect to Maize ; on V orbascum, idem, ss. !)2 and 181 ; also his 'Konntniss dcr Bcrfmchtung,' s. 137. With respect to Nicotiaun, see Kolrcuter, 'Zwoite Forts.,' 1764, s. 53 ; though this is a somewhat different case. 1a~ ' Do l'Espcce,' par M. Godron, tom. ii. p. G4. . CUAl', X. CUCUil.BITACEOUS PLANTS • 359 referring to the species of CucUl'bita, says, " au milieu do toutes les variations du fruit, lea tiges, lea feuilles, los calices, les corolles, los 6tamines rcstont invariablos dans chacune d'ollcs." Yet M. Naudin in describing Cuwr·bita pepo (p. 30) says, "Ici, d'ailleurs, ce no sont pas soulement los fruits qui variant, c'cst aussi lo feuillage et tout le port do la planto. N canmoins, je crois qu'on Ia ilistingucra toujours facilcment des deux autres espcccs, si l'on vcut ne pas perru·o de vue los caracteres iliffcrentiels que je m'offorco de faire ressortir. Cos caractcres sont quelquofois pou marques : il arrive memo quo plusieurs d'ontre eux s'effacent presque enticrcment, mais il en rcsto toujours quclquos-uns qui romettent l'observateur sur la voie." Now let it be noted what a ilifl'erenco, with regard to the immutability of tho so-called specific characters, this paragraph produces on the mind, from that above quoted from lVI. Godron. I will add another remark: naturalists continually assert that no important organ varies; but in saying this they unconsciously aTgue in a vicious circle; for if an organ, let it be what it may, is highly variable, it is regarded as unimportant, and under a systematic point of view this is quito correct. But as long as constancy is thus taken as the criterion of importance, it will indeed be long before an impoTtant organ can be shown to bo inconstant. The enlarged form of tho stigmas, and their sessile position on the summit of tho ovary, must be considered as important characters, and were used by Gasparini to separate certain pumpkins as a dist'inct genus; but Naudin says (p. 20) these parts have no constancy, and in the flowers of the Turban varieties of G. maxima they sometimes l'Csume their ordinary structure. Again, in G. maxima, the carpels (p. 19) which form tho Turban project even as much as two-thirds of their length out of tho receptacle, and this latter part is thus reduced to a sort of platform; but this remarkable structure occlil's only in certain varieties, and graduates into the common form in which tho carpels are almost entirely enveloped within the rccoptaclo. In G. moschata the ovarium (p. 50) varies greatly in shape, being oval, nearly spherical, or cylindrical, more or less swollen in the upper part, or constricted round tho middle, and either straight or curved. When tho ovarium is short and oval the interior structme docs not iliffcr from that of G. max'ima and pepo, but when it is elongated the carpels occupy only the terminal and swollen portion. I may add that in one variety of tho cucumber ( Cttc~tmis sativus) the fruit regularly contains five carpels instead of three.14o I presume that it will not bo disputed that we here have instances of great variability in organs of the highest physiological importance, and with most plants of the highest classificatory importance. Sagerct 141 and Naudin found that tho cucumber (G. sativus) could not be crossed with any other species of the genus ; therefore no doubt it is specifically distinct from tho melon. This will appear to most persons a superfluous statement; yet we hear from N au din 142 that there is a race HO Nnudin, in' Annal. des Sci. Nat.,' 4th scr. Bot. tom. xi. 1859, p. 28. 141 'Memoi.re sur los Cucurbitucccs ' 1826, pp. 61 24, I 142 'Flore des Serres,' Oct. UlGl, quoted in' Gardener':; Chronicle,' 1861, p. 1135. I have also consulted and tn,kon some facts from M. N audiu'H |