It is well known that many plants appear to select certain mineral soils and avoid others, that a number of plants which prefer calcareous soils are grouped together as calcicoles, and others which shun such ground 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 existing about it. Here are found Alpine, maritime, and exotic plants associated in a common isolation.--Revue Scientifique.
RECENT BOTANICAL ADVANCES.
Among the most significant of the recent discoveries in botany, is that respecting the continuity of the protoplasm from cell to cell, by means of delicate threads which traverse channels through the cell walls. It had long been known, that in the "sieve" tissues of higher plants there was such continuity through the "sieve plates," which imperfectly separated the contiguous cells. This may be readily seen by making longitudinal sections of a fibro-vascular bundle of a pumpkin stem, staining with iodine, and contracting the protoplasm by alcohol. Carefully made specimens of the soft tissues of many plants have shown a similar protoplasmic continuity, where it had previously been unsuspected. Some investigators are now inclined to the opinion that protoplasmic continuity may be of universal occurrence in plants.