1878. | Botany. 389 
Botany. From animals plants are protected by possession of 
runners ; by close growth (thus effectually banishing animals too 
large to force a passage); by growing under sheltering bushes 
(this applies of course to herbs); by twining habits ; by epiphytic 
habits; by presence of spines and thorns (protection against 
grazing birds); by all forms of trichomes (these, besides hindering 
browsers, prevent crawling up of insects, &c.); by production of 
organs and tissues suitable to ant-habitation ; by growing in water, 
and by having leaves adapted to hold water at their bases; by 
rings of hairs on stems, &c. (against crawling insects) ; by slippery, 
waxy surfaces; by milky sap (this, besides being poisonous to 
grazing animals, by its exudation impedes the movements of small 
climbing creatures); by presence of ethereal oil in all parts, in- 
animals; by development of tubers, bulbs and allied structures ; 
by revolution of leaf margins and of corolla-tips (renders climb- 
ing difficult to ants); by the absence of chlorophyll; by poisonous 
or bitter principles developed chiefly in seeds, these also being 
protected by their hardness, leathery consistence and small size. 
Protections against unfavorable weather are — runners (which 
support plants against over-weight of snow in alpine and polar 
regions, and by admitting of a complete covering of snow are 
enabled to resist the otherwise fatal effects of frost); aériel roots 
—props against land-storms and dash of the waves; gregarious 
habits lessening the force of the winds, a result accomplished 
also by the horizontal position of the branches, by development 
of small scaly leaves, and by possession of leafy crowns, deep 
roots and strong or slim stems; hairy clothing, which protects 
against cold, rain and undue transpiration, and also intercepts and 
retains rain and dew;; irritability to light or touch; possession of 
a waxy outer layer and of a strong cuticle; a thick sap which, 
owing to the hygroscopic property of its solid constituents, keeps 
the circulation active during the period of greatest sun-heat and 
dry season; ethereal oils which gradually evaporating, produce 
resin, a layer of which‘accumulating on the evaporating surfaces, 
lessens the amount of transpiration; the thick sap of plants 
growing in deserts, when the difference between the temperatures 
of day and night is very great, protects them against injury from 
the daily great variations of temperature; phyllodes, and leaves 
occupying the position of phyllodes, being less transpirable, are 
adaptations to a dry climate; presence of corky tissues which 
protects against frost, etc., absence of stomata, which in some 
cases prevents entry of thawing snow ; thickened roots, &c., which 
are stores of nutriment and water, and preserve life during times 
of drought; besides the many arrangements by which the repro- 
ductive organs are protected from rain, dew and wind. 
