Scientific American Supplement, No. 430, March 29, 1884 by Various
page 9 of 132 (06%)
page 9 of 132 (06%)
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as _calcifuges_. Herr Hoffman has grown the specimen which has been
cited by many authors as absolutely calcifugic. He has obtained strong plants upon a soil with 53 per cent. of lime, and these have withstood the severe winter of 1879-1880, while individuals of the same species grown on silicious ground have failed. This will modify the ideas of agriculturists, at least in regard to this plant. Herr Schwarz has been engaged in the study of the fine hairs of roots. According to this author, there is a maximum and minimum of humidity, between which there lies a mean of moisture, most favorable for the development of these capillary rootlets, and this amount of moisture varies with different plants. He finds that this growth of hair-like roots is conditioned upon the development of the main root from which it springs. In a weak solution of brine these fine roots are suppressed, while the growth of the main root is continued. The changes of the _milieu_ lead to changes in the form of the hairs, rendering them even branched. Signor Savastano has ventured to criticise as exaggerated the views of Muller, Lubbock, and Allen on the adaptation of flowers to insects, having noticed that bees visit numbers of flowers, and extract their honey without touching the stigmas or pistils. He has also found them neglecting flowers which were rich in honey and visiting others much poorer. These observations have value, but cannot be considered as seriously impairing the multiplied evidences of plant adaptation to insect life. Mr. Camus has shown that the flora of a small group of hills, the Euganean Mountains, west of the Apennines and south of the Alps, has a peculiar flora, forming an island in the midst of a contrasted flora |
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