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Show 360 PLANrrs STERILE WITHOUT INSECrr-AID. CIIAP. X. ) produced two fruits. It is probable that different var~eties would differ in this respect, as some are only feebly dichogamous. J)ionth"s caryophyllus (Caryopl1yllaccm).-Produces very few capsules, which contain any good seeds. . fJhaseolus multt;florus (Leguminosro).- Plants protected from insects produced on two occasions about one-third an~ oo~eighth of the full number of . eeds: soc my arhcle m 'Gardeners' Chronicle,' 1857, p. 22G, and 1858, p. 828; alRo 'Annals and 1\iag. of Natural History,' 3rd sm·jcR, vol. ii. 1858, p. 462. Dr. Ogle(' Por). Science Review,' 1870, p. 168) found that a plant was quito sterile when covered np. The flowers are not visited by insects in Nicaragua, and, according to Mr. Belt, tho species is thoro qnito sterile: 'The Naturalist in Nicaragua,' p. 70. Viciafaba (Legumino re).-Sovonteen covered-up plants yielded 40 beans, whilst seventeen pla.nts left unprotected and growin()' close alongside produced 135 beans; those latter b . plants wore, therefore, between throe and four times ~or~ fertile than tho protected plants: soc' Gardeners' Chromclc for fuller details, 1 58, p. 828. Rrythrinn (sp. ?) (Leguminosm).-Sir vV. MacArthur informed mo that in New South Wales tho flowers do not sot, unless the petals are moved in tho same manner as is clone by insects. Lathyrus ylandiflorus (Logurninosro ).-Is in this country m~r? or less sterile. It never sots pods unlo. s tho flowers arc VISited by humble-bees (and this happen. only rarely), or unlDss they are artificially fertilised : soc my article in ' Gardener~' Chronicle,' 1858, p. 8:28. . Sarothamnus scoparius (Leguminosm).-Extrcmoly stenlo when the flowers are neither visited by bees, nor disturbed by being beaten by the wind against tho Rurrounding net ... JI!Itlilotus officinal is (Leguminosro ).-An unprotected plant VJSitccl by bees produced at least thirty times more seeds than a protected one. On this latter plant many scores of racemes did not produce a single pod; several raccm?s pro~luced each one or two pods; five produced throe; SIX procluce~ four· and one produced six pou . On tho unprotect~d plan each' of several racemes prouueec.l fifteen pods; mno produced between sixteen and twenty-two pods, and one produced thirty pods. CHAP. X. PLANTS STERILE WITHOUT INSECT-AID. 361 Lotus corniculatus (Leguminosm).-Several covered-up plants produced only two empty pods, and not a single good seed. Trifolium repens (Leguminosm).-Several plants were protected from insects, and the seeds fr01n ten flower-heads on these plants, and from ton heads on other plants growing outside the net (which I saw visited by bees), wore counted; and the seeds from the latter plants were very nearly ten times as numerous as thoRe from the protected plants. The experiment was repeated on the following year; and twenty protected heads now yielded only a single aborted seed whilst. t:vcnty heads on the plants outside the net (which I sav; v~sitod by bee:;;) yielded 2290 seeds, as calculated by Weighing all the seed, and counting thA number in a weight of two grains. T. pratense.-One hundred flower-heads on plants protected by a net did not produce a single seed, whilst 100 head. on plants growing outside, which were visited by bees, yielded 68 grains weight of seeds; and as eighty seeds weighed two grains, the 100 heads must have yielded 2,720 seeds. I have often; watched this plant, and have never seen hive-bees sucking the flowers, except from the outside through holes bitten by humble-bees, or deep down between the flowers as if in search of some secretion from the calyx, almost in the same manner as described by 1\ir. Farrer, in the case of Coronilla ('Nature,' 1874, July 2, p. 169). I must, however, except one occasion, when an adjoining field of sainfoin (lltdysarum onobrychis) had just been cut down, and when the bees seemed driven to desperation. On this occasion most of the flowers of tbe clover were somewhat withered and contained an extraordinary quantity of nectar, which' tho bees were able to suck. An experienced apiarian, Mr. Miner, says that in the United States hive-bees never suck the red clover; and 1\ir. n. Colgate informs me that he bas observed the same fact in New Zealand after the introduction of the hive-bee into that island. On the other hand, H. Miiller (' Tiefruchtung,' p. 224) has often seen hivebees visiting this plant in Germany, for the sake both of pollen and nectar, which latter they obtained hy breaking apart the petals. It is at least certain that humble-bees are the chief fertilisers of the common red clover. T. inca1·natum.-The flower-heads containing ripe seeds, on some covered and uncovered plants, appeared equally fine, but |
