918 



GLOSSARY. 



Invertin, a ferment which converts cane-sugar into 



glucose. 

 Involucral, appertaining to the involucre. 

 Involucre, a circle of bracts inclosing a capitulum 



or utlicr crowded inflorescence. 

 Involute, rolled inward. 



Isogametes, equivalent gametes or sexual cells. 

 Isoplanogametes, in Algae ; motUe sexual cells whicli 



are ec^ual in size. 



Kamptodromous. See vol. L p. 630. 



Labellum, the median member of the inner perianth- 

 whorl in Orchids. 



Laciniated, cut into narrow lobes. 



Lacuna, a space, especially an intercellular space, 

 originating by the separation or breaking down of 

 cells. 



Lamella, a thin plate as in the gUls of Agarics. See 

 Gills. 



Lanceolate, shaped like a lance-head ; narrower 

 than oblong, and tapering towards the apex. 



Latex, plant juice, often a milky juice. 



Laticiferous, containing latex. 



Leaf- axil, the angle formed by a leaf and the por- 

 tion of stem immediately above its point of inser- 

 tion. 



Leaves, laterally - developed members of limited 

 growth, whicli spring in geometrical succession 

 from tlie outer layers of tissue below the growing 

 point of the stem. 



Legitimate union, in heterostyled flowers. Vide 

 vol. Ü. p. 405. 



Legume, or Pod ; a monocarpellary fruit dehiscing 

 down both sutures. 



Lepidote, -us, beset \vith scurfy scales. 



Liane, Liana, a climbing plant with a woody, peren- 

 nial stem. 



Libriform cells, strong, spindle-shaped cells witli 

 inconspicuous pittings, thick walls, and usually 

 destitute of protoplasmic contents. They occur in 

 wood. 



Lichen, an organism compounded of a Fungus and an 

 Alga li\'ing together symbiotically. 



Lignin, an aromatic substance (or number of sub- 

 stances) present in the membrane of woody tissue. 

 To it are due the characteristic properties of wood. 



Ligulate, provided with a ligule. 



Ligule, Ligula, (1) the thin scarious projection from 

 the summit of the leaf-sheath in Grasses ; (2) the 

 corolla of a ray-floret in the Compositie ; (3) a 

 tongue-Uke outgrowth on the leaf met with in Sela- 

 ginella and Isoetes just above the insertion of the 

 sporangium. 



Linear, several times narrower than long, with the 

 margins parallel. 



Linear-lanceolate, intermediate in form between 

 linear and lanceolate. 



Lines of vegetation, for any species, are the Hnes 

 obtained by joining all the places in a given direc- 

 tion at whicli that species is checked in its distribu- 

 tion by climatic or other conditions ; the resultant 

 figure obtained by joining all the lines of vegetation 

 covers the distribution of the species in question, 

 and may be termed the line of distribution. 



Lithophytes, plants which grow on stones, and 

 derive their nutriment in tlie main from the atmo- 

 sphere. 



Liverwort, a term applied to any member of the 



Hepaticie. 

 Lobe, any division of an organ ; a rounded projection 



or division. 

 Lodicules, tiny scales, usually two in number, which 



occur in the flowers of Grasses, and are supposed to 



represent the perianth. 

 Lomentum, a legume which separates into 1-seeded 



articulations or joints. 



Macropodous, applied to embryos in which the 

 hypocotyl is enormously enlarged, constituting the 

 greater part of the embryo. 



Macrospores, used of the larger (so-called female) 

 spores of heterosporous plants: opposed to micro- 

 spores. 



Manubrium, the cell in the antheridium of Chara- 

 cefe which projects inwards from the shield, and 

 ultimately bears the antheridial filaments. 



Medulla, pith. 



Megagametes, used of the larger, and presumably 

 female, motUe sexual cells of certain Algse. 



Melliferous, honey-bearing. 



Meiicarp, one of the achene-like fragments into 

 which a syncarpous, polycarpellary fruit (schizocarp) 

 breaks up. Used especially of Umbellifer8e. 



Meristem, embryonic tissue: growing cell tissue at 

 the ends of young stems, roots, &c. 



Mesophyll; the whole of the internal grotmd-tissue 

 of a leaf-blade. 



Metabolism, the chemical changes which take place 

 in the protoplasm and which it causes in other sub- 

 stances ; the phenomena resulting from chemical 

 changes in the protoplasm. 



Micellae, name given to molecular aggregates, just as 

 molecule is the name given to atomic aggregates. 



Microgametes, used of the smaller, presumably male, 

 motile sexual cells of certain Algae. 



Micro-millimeter (^), the one-thousandth part of a 

 millimeter. 



Micropyle, the aperture left in the integument of 

 an ovule by means of which the pollen-tube gains 

 access (except in chalazogamic plants) to the 

 emliryo-sac. 



Microsomata, tiny granules of various nature em- 

 bedded in the protoplasm. Not a good term. 



Microspores, the smaller or so-called male spores of 

 heterosporous plants: opposed to viacrosporrs. 



Midrib, the central or main vascular bundle of a leaf, 



Monadelphous, when the stamens are all united 



together by their filaments into a tube or column. 

 Monandria, the 1st class of the Linnean system. See 



vol. ii. p. 2SS. 

 Moniliform, Hke a necklace or string of beads. 

 Monocarpellary, consisting of one carpel. 

 Monocotyledonous, having only a single cotyledon 



or seed-leaf. 

 Moncecia, the 21st class of the Linnean system. 



See vol. ii. p. 290. 

 Moncecious, having male and female flowers on the 



same individual. 

 Monotypic, term used of genera which comprehend 



but a single species, e.g. Welwitschia. 

 Morphology, that department of botanical study 



wliicli deals with the form of the plant -body, 



including its development, the growth of its distinct 



members, &c. 



