360 PLANTS STERILE WITHOUT INSECT-AtD. Chap. X. 



produced two fruits. It is probable that different varieties 

 would differ in this respect, as some are only feebly dicho- 

 gamous. 

 Diunthus caryopliyllus (Caryophyllaceao). Produces very few 



capsules, which contain any good seeds. 

 Phaseolus multiflorus (Leguminoste). Plants protected from 

 insects produced on two occasions about one-third and oae- 

 eighth of the full number of seeds: see my article in 

 ' Gardeners' Chronicle,' 1857, p. 225, and 1858, p. 828 ; also 

 ' Annals and Mag. of Natural History,' 3rd series, vol. ii. 

 1858, p. 462. Dr. Ogle (' Pop. Science Eeview,' 1870, p. 168) 

 found that a plant was quite sterile when covered up. The 

 flowers are not visited by insects in Nicaragua, and, accord- 

 ing to Mr. Belt, the species is there quite sterile : The 

 Naturalist in Nicaragua,' p. 70. 

 Viciafaba (Leguminosse). Seventeen covered-up plants yielded 

 40 beans, whilst seventeen plants left unprotected and 

 growing close alongside produced 135 beans; these latter 

 plants were, therefore, between three and four times more 

 fertile than the protected plants : see ' Gardeners' Chronicle ' 

 for fuller details, 1858, p. 828. 

 Erythrina (sp. ?) (Leguminosas). Sir W. MacArthur informed 

 me that in New South Wales the flowers do not set, unless 

 the petals are moved in the same manner as is done by 

 insects. 

 Lathyrus grandiflorus (Leguminosag). Is in this country more or 

 less sterile. It never sets pods unless the flowers are visited 

 by humble-bees (and this happens only rarely), or unless 

 they are artificially fertilised : see my article in ' Gardeners' 

 Chronicle,' 1858, p. 828. 

 Sarothamnus scoparius (Leguminosae). Extremely sterile when 

 the flowers are neither visited by bees, nor disturbed by 

 being beaten by the wind against the surrounding net. 

 Melilotus officinalis (Leguminosas). An unprotected plant visited 

 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 racemes produced 

 each one or two pods; five produced three; six produced 

 four; and one produced six pods. On the unprotected plant 

 each of several racemes produced fifteen pods ; nine pro- 

 duced between sixteen and twenty-two pods, and ona 

 produced thirty pods. 



