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Show PLANTS STERILE WITHOUT INSECT-AID. CHAr. X. r. t1·icolor.-Sets very few and poor capsules. . . Reseda odorata (Resedacere).-Some individuals quite stcnle. R. lutea.-Some individuals produce very few and poor cap-sules. . . . . Abutilon dm·winii (Malvacere).- Quite sterile In Brazil : sec previous discussion on self-sterile plants. Nymphrea (Nymphreacere).-Pr_ofessor. C~s~ary informs me that some of the species are quite sterile If Insects are excluded. Enryale amazordca (Nymphreacero).-Mr. J. Smith, of Kew, informs me that capsules from flowers left to themselves, and probably not visited by insects, contained from eight to fifteen seeds ; those from flowers artificially fertilised with pollen from other flowers on the same plant cont~i~cd fr~m fifteen to thirty seeds; and that two flowers fertilised w1th pollen brought from another plant at Chatsworth conta~ncd Tespectively sixty and seventy-five seeds. I have g1vcn these statements because Profe or Caspary adva.nccs this plant as a case opposed to the doctrine of the necessity or advantage of cToss-fertilisation: see Sitzungsbcrichtc dcr Phys.-okon. Gesell. zu Konigsberg, B. vi. p. 20. Delphinium consolida (Ranunculacere).-Produces many capsules, but these contain only about half the number of seeds compared with capsules from flowers naturally feTtilised by bees. Eschscl,oltzia californ·ica (Papaveracere).-Brazilian plants quite sterile: English plants produce a few capsules. Papnver vagum (Papavcracem).-In the early part of the summer pToduced very few capsules, and these contained very few seeds. P. alpinum.-I-I. Hoffmann (' Speciesfrage,' 1875, p. 47) shtteH that this species produced seeds capable of germination only on one occasion. Oo:rydaUs cava (Fumariacere ).-Sterile : sec the previous discus-sion on self-sterile plants. U. salida.-I had a single plant in my garden (1863), and saw many hive-bees sucking the flowers, but not a single seed was produced. I was much surprised at this fact, a~ P~ofessor Hildebrand's discovery that 0. cava is sterile with Its own pollen had not then been made. He likewise concludes from the few experiments which he made on the present species that it is self-sterile. The two foregoing cases are interesting, because botanists formerly thought (sec, for UnAr. X. PLANTS STERILE WI'riiOUT INSECT-AID. instance, Locoq, '.De la Fecondation ct de l'Hybridation,' 1845, p. 61, and.Lin~ley, 'Vcgct~ble Kingdom,' 1853,p. 436) that all the spccws of the Fumanaccm wore specially adapted for self-fextilisa ti on. . 0. lutea.-A covered-up plant produced (1861) exactly half as ~any capsules as an exposed plant of the same size growIng close alongside. When humble-bees visit the flower~ (and I repeatedly saw them thus acting) the lower I etals suddenly spring downwards and the pistil upwards· this is due to the elasticity of the prtrts, which takes eff:ct, a~ soon as the coherent edges of the hood are separated by the entrance of an insect. Unless insects visit the flowers the parts do not move. Nevertheless, many of the flowers on the plants which I had protected produced capsules, notwithstanding that their petttls and pistils still retained their original position; and I found to my surprise that the. e capsules contained more seeds than those from flowers, the petals of which had been artificially separated and allowed to spring apart. Thus, nine capsules produced by undisturbed flowers contained fifty-three seeds; whilst nine capsules from flowers, the petals of which had been artificially separated, contained only thirty-two seeds. But we should remember that if bees had been permitted to visit these flowers, they would have visited them at the best time fol' fertilisation. The flowers, the petals of which bad been artificially separated, set their capsules before those which were left undisturbed under the net. To show with what certainty the flowers are visited by bees, I may add that on one occasion all the flowers on some unprotected plants were examined, and every single one had its petals separated; and, on a second occasion, forty-one out of fortythree flowers were in this state. Hildebrand states (Pring. Jahr. f. wiss. Botanik, B. vii., p. 450) that the mechanism of the parts in this species is nearly the same as in 0. och1'o-leuca, which he has fully described. · Ifypecoum grund~florum (Fumariacere).-Highly self-sterile (Hildebrand, ibid.). Kalmia latifolia (Ericacere).-Mr. vV. J. Beal says ('American Naturalist,' lt)67) that flowers protected from insects wither and drop off, with "most of the anthers still remaining in the pockets." Pelargonium zonale (Geraniaccre).-Almost sterile; one plant |