916 



GLOSSARY. 



Ethereal oils, oils of wide occurrence in plants, and 



of various chemical composition ; to the presence of 



these ethereal or volatile oils are due most of the 



odours of plants. 

 Evolute, turned back. 

 Exalbuminous, applied to seeds which are destitute 



of endosperm or perisperm, the food-material being 



stored in the embrj'o itself. 

 Excoriation, of glandular hairs ; applied to the act 



of throwing off the cuticle as a blister. 

 Exfoliate, to come away in scales or flakes, as the 



bark of a tree. 

 Exine. See Extine. 

 Exogamy, the tendency often exhibited by closely 



related gametes to avoid pairing. 

 Exosmosis, the passage from within outwards of 



fluids through a membrane. 

 Exothecium, the outmost layer or epidermis of an 



anther. 

 Exstipulate, without stipules: often used (though 



erroneously) in cases where the stipules are early 



deciduous. 

 Extine, the outer coat or membrane -layer of a pollen- 

 grain. It is, however, internal to the perine. 

 Extravasation, an escape from the proper vessels into 



surroimding tissues : used of fluids. 

 Extrorse, appUed to such anthers as open towards 



the outer whorls of a flower, i.e. away from the 



gynoeceum. 

 Eye, of Potato, &c. ; an undeveloped bud. 

 Eye-spot, in motile gametes and spermatozoids, a 



little red pigment-body contained usually in the 



anterior extremity, and supposed to be sensitive to 



Ught. Cf. vol. ii. p. 629. 



Fairy-ring, a phenomenon observed in meadows, and 

 due to the growth of certain Fungi. Cf. vol. ii. 

 p. 792. 



Fasciation, used of monstrous expansions of stems, 

 which resemble several stems fused together in one 

 plane. 



Fascicula, or Fascicle, a dense cluster of flowers, 

 leaves, roots, &c. 



Father-plant, the stock from which the pollen is 

 derived : used in connection ^\"ith hybrids. 



Ferment, a substance produced by the protoplasm, 

 which induces chemical change or fermentation in 

 some substance without itself entering into or being 

 affected by the process. 



Fertilization, the process by which the pollen reaches 

 and acts upon the ovules, and results in the produc- 

 tion of fruit ; impregnation. 



Fertilizing-tube, in Peronospora, the tubular out- 

 growth of the antheridium which penetrates the 

 oogonial wall and by which the male substance 

 passes to the egg-cell. 



Fibre, any delicate filament; also, a thick- walled 

 tapering cell. 



Fibrils of nucleus ; the segments into which the 

 nuclear reticulum breaks up at division ; they are 

 also termed chromosomes. 



Fibrous layer, of anther: the specially thickened 

 portion of the wall which brings about dehiscence. 



Filament, the staUc of an anther. 



Filiform, slender, thread-Uke. 



Fimbriate, fringed by fine subdivision of the margin; 

 having fine, hair-like marginal processes. 



Fistular, hollow, reed-like. 



Flagellum, the whip-like process or filament of proto- 

 plasm which serves as an organ of motility ; also a 

 shoot sent out from the bottom of a stem, as in the 

 strawberry ; a runner. 



Floccose, composed of or bearing soft hairs or wool. 



Flora, the .aggregate of the plant-population of any 

 district; also, the term given to a systematic descrip- 

 tion of the same. 



Floral, belonging to the flower. 



Floret, a small flower in a cluster or in a compact 

 inflorescence, as in the Composite. 



Flower, in Phanerogams the growth which comprises 

 the reproductive organs and their envelopes; a shoot 

 modified for the production of spores (pollen-grains 

 and embryo-sacs). 



Flowering glume, the outer of the two chaffy scales 

 inclosing the several flowers of a grass ; it is fre- 

 quently awned. 



Folium fulcrans, the subtending leaf of a flower; 

 a bract. 



Follicle, a monocarpeUary dehiscent fruit opening 

 only down the ventral sutui-e. 



Foot, the sucker by means of which a young Fern- 

 plant is temporarily attached to the prothallium. 



Foreign, applied to pollen from another flower. 



Frugivora, animals which live upon fruits. 



Fruit, defined vol. ii. p. 47. 



Frustule, the siliceous valve of a Diatom. 



Frutex, a shrub. 



Fruticose, pertaining to shrubs ; shrubby. 



Fruticulus, a little shrub. 



Fuliginous, ha\ing the colour of soot. 



Fundamentum, the hypocotyl, which see. 



Fungus, a cellular Cryptogam, distinguished for its 

 want of chlorophyll; it is either saprophytic or 

 parasitic. 



Funicle, the stalk of an ovule or seed; a ftmiculus. 



Furfuraceous, scurfy; covered with bran-Uke scales. 



Fusiform, spindle-sh.aped: applied to roots, &c., which 

 taper both ways from the middle, as the radish. 



Galeate, helmet-shaped; ha^-ing a galea or helmet. 



Gall, a vegetable excrescence produced by the deposit 

 of the egg of an insect in the bark or leaves of a 

 plant; a hypertrophied growth due to some irritat- 

 ing cause. 



Gametangia, cells from which gametes are developed. 



Gamete, a sexual cell. 



Geitonogamy, crossing between sepai-ate flowers 

 growing on the same plant. 



Gemma, a small undeveloped shoot; a shoot-bud. 



Gemmation, the act or process of budding. 



Generative cell, in pollen-grains, that cell which 

 ultimatelj' fertilizes the egg-cell. 



Genetic spiral, the spiral line passing through the 

 point of insertion of equivalent lateral members 

 (leaves) on an axis in order of age from older to 

 younger. 



Genus, an assemblage of species; its name, together 

 with that of the species, gives the name to the 

 plant. 



Geotropism, applied to the power or tendency of 

 some jilunts to grow towards the earth. 



Germcn, the ovary. 



Germination, the act, process, or result of evolving 

 the embryo of a seed into a young plant. 



