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ELEMENTARY BOTANY. * HI 



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without penetrating into their tissue, parasites when their roots penetrate into and 

 derive more or less nutriment from the plant to which they are attached. 

 15. The simplest form of the perfect plant, the annual, consists of— 



(1) The Root, or descending axis, which grows downwards from the stem, 

 divides and spreads in the earth or water, and absorbs food for the plant through 



the extremities of its branches. •. i. v i 



(2) The Stem, or ascending axis, which grows upwards from the root, oranchea 

 and bears first one or more leaves in succession, then one or more flowers, and nnaAly 

 one or more fruits. It contains the tissues or other channels (217) by which the 

 nutriment absorbed by the roots is conveyed in the form of sap (11)2) to the leaves 

 or other points of the surface of the plant, to be elaborated or digested (218), and 

 afterwards redistributed over different parts of the plant for its support and growth. 



(3) The Leaves, usually flat, green, and horizontal, are vanously arranged on 

 the stem and its branches. They elaborate or digest (218) the nutriment brought to 

 them through the stem, absorb carbonic acid gas from the air, exhaling the super- 

 fluous oxygen, and returning the assimilated sap to the stem. _ _ , . , v t, 



(4) The Flowers, usually placed at or towards the extremities of the branches. 

 They are destined to form the future seed. When perfect and complete they con- 

 sist: 1st, of a pistil in the centre, consisting of one or more carpejs, each containing 

 the germ of one or more seed* ; 2nd, of one or more stamens outside the pistil, whose 

 action is necessary to fertilize the pistil or enable it to ripen its seed ; ^m, oi a 

 perianth or floral envelope, which usually encloses the stamens and pistil when 



: young, and expands and exposes them to view when fully formed, ihis complete 

 perianth is double : the outer one, called Calyx, is usually more green and leat-UKe , 

 the inner one, called the Corolla, more conspicuous, and variously coloured, n is 

 the perianth, and especially the corolla, as the most showy part, that is generally 



caUed the flower in popular language. ,. ... „_„;„+„ r,r- 



; (6) The Fruit, consisting of the pistil or its lower portion, ^^ich persists or 

 remains attached to the plant after the remainder of the flower has ^thered and 

 fallen off. It enlarges an^ alters more or less in shape or <^"°«'stence becomes a 

 »eed-vessel, enclosing the seed until it is ripe, when it either opens to discharge the 

 seed or falls to the ground with the seed. In popular language *1^? *e"".{.7^'. '' 

 often limited to such seed-vessels as are or look juicy and eatable. Botanists give 



that name to all seed-vessels. ■ , , • i.i c <. xroar nt its 



• 16. The herbaceous perennial resembles the annual during the fi^s* y^^r ot its 

 growth ; but it also forms (usually towards the close of the season , on its «<orMtne 

 portion of the stem and root which does not die), one or more buds ether exposed, 

 and then popularly called eyes, or concealed among leaves. These ^"^8, ^all^^^^ 

 re:.^,f \^^-p4 t^em fLnflou-cr-buds or.-oVer^e^,^Z'Z'ZiZ 'Jwng 



dormant 



— jcu uuueveioped ; they remain dormani, tmou-i. ^..- •■—--' , f .-. __„. 



spnng grow out into new stems bearing leaves and flowers like t^/^^^ «{ Jf ^'^ 

 ceding year, whilst the lower part of the stock emits fresh roots to replace those 



■Which had i)erished at the same time as the stems. ^..+rom;tv of their 



, 17. Shrubs and trees form similar leaf-buds either at the ^^tremity of the^r 

 branches, or along the branches of the year. In_ be atter ca e t^ e Ju^^s -« 



distinct 



„j, i,i,c ieai auu lae urancu. y» ucu u.icj ^^i ;-.- - ., - , distinct 



tbey are called adventitious. If these Inids by producing roots J^^) ,';«"'J™^,^„ced 

 plants before seijarating from the parent, or^f adventitious leaf b^^s are prouuc 

 "1 the place of flowers or seeds, the plant is said to be vtvijparow, or proliferoi 



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§ 2. The Root. 



Their 



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18 Roots ordinarily produce neither buds, leaves, nor ^owew- Th^^r ram. • 

 <^^m fibres when slender and long, proceed irregularly from ^'^y^'^^^X [hey may 

 ^19. Although roots proceed u^ally from the base of «^«/S ^^^e' S th^ 

 ^o be produced from the base of any bud, especially if th«DUd | ^^^ 



g«>und. or is otherwise placed by nature or art in cm«.m^^^^^^^^^ 



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