ELEMENTARY BOTANY 



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leaves or Wanches, tlie fleshy, woody, or bony parts of fruits, the albumen, and the 

 thick fleshy parts of embryos, consist chiefly of largely developed cellular tissue 

 replete with starch or other substances (192), deposited apparently in most cases 

 for the eventual future use of the plant or its parts when recalled mto activity at 



the approach of a new season. . ,, ., . „„3 „„„:af 



■' 205. Hairs (171) are usually expansions or processes of the epidermis, and consist 

 of one or more cells placed end to end. When thick or hardened mto Pickles they 

 still coQsist usually of cellular tissue only. Thorns (1 70) contam more or less ot a 

 fibro vascular system, according to their degree of development . ^ofT^^r 



' 206. Glands, in the primary tense of the word (175, I), consist usually of a rather 

 loose cellular tissue without epidermis, and often replete with resinous or otner 

 substances. 



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ring the dead season, or at any other time, lue S^"";";"; Xtacle op- 

 '^u.ott, dried up, or otherwise injured, or stopped by a rock or otl^^^r obstacle op 

 posing its nrogress. lateral fibres will be formed on the still living portmn ' ^^J^^f 

 tabling the root as a whole to diverge in any di 



W^vl? brthe successive formation of terminal cells 



uuwevci ujr lu f^^^^A nr^ a fihre commencing or 



This growth is not. ho wftvfir by tne successive ikjilx±<mv^^^^ -- — '"\.^;r^n^ nr 



^, . - . Th^e cells fii.t formed on a A^re cc,mmencing.or 



«newing 



^ttainin 



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'207. Roots grow in length constantly and regularly at the extremities only of 

 their fibres, in°proportion as they And the requisite nutriment. They form no buds 



containing the germ of future branches, but their ^^^^^^l^'^T '''^'^^^J'^ 

 Wmt of their surface without previous indication, and when their ^^^^ ^^ 

 l«en stopped for a time, either wholly by the close of the season, or P™; y ^y 

 ,«. deficiency of nutrimeAt at any particular spot, it will, on the ^^^'1™ of favourable 

 circumstances, be resumed at the same point, if the growing extremities be unm 

 jwed. If during the dead season, or at any other time, the growing extrem^ity is 

 cut off, dried up, or otherwise injured, or stopped by a rock 



wide 



■'^ben lured 



3 growth'i 

 t once th( 



,--« 'ts growth, will often dry up and torm a *^'"^,"^,''"""'"";.TiT' „onsti- 

 « pushed on al cells ^re formed immediately under it ; and ^^e.^^^^^^f^' "''"if a 

 t^tmg a greater or lesser portion of the ends of the fibres, remain some time in a 

 groviing state before they have attained their full size. ^_ , 



^209 The roots of Exogens, when perennial, increase m JV'^ Ztinotlv m^ked^ 

 fte addition of concentric lasers, but these are usually much ^^^s distinctly marked , 

 «^d in a large number of per Jnnial Exogens and most Endogens tbe i-oots^^^^^^^ 

 P^nshing at the close of the season, fresh adventitious roots sprmging from tne 

 stock when vegetation commences the following season. . . . 



,^210. The stem, including its branches and appendages Reaves, floral oi^ganse^^^^^^ 



f ows in length by additions to its extremity, but a much g^^at^^ P^^P*^/^;"" ^^^eh 

 «f remity and branches remains in a growing and expanding state tor ^ j 

 onger time than in the case of the root.^ At the close of one Reason leaf buds or 

 seeds are form^, each containing the germ of a branch or you^g plant to be pro 

 J°ced the following season. At a very early stage of t^^^ development o^ tnese 

 Ws or seeds, a commencement may be found of many of the leavf it ^s to bear 

 ^d be ore a leaf unfolds, every leaflet of which t is to consist, ^^ ^ry h^be or too 

 fM} 18 to mark its margin, may often be traced m miniature, and t^L^^^f^f '^^^^^3 

 J attains ita full size, the bmncli grows and expands in every part jfj^^^'^^^^ 



f2«ver the lower part of a branch and more rarely ('vf- J^^,^,7i™ "r S^ets 

 y « part of a compound leaf attains its full size before the young lea% es lea 



o?f ^'Jtremity are yet formed. . ,, •!,„„„, >,v the addition 



.211. The perenniafstem, if exogenous (198), grows in ""^kness ^y * ^ e a 

 Sl««^on of a new lave^ or ring of wood between the ^termost precedi g j ^^ 

 W i'/r^^"^^^^ °f «^« bark,°and by the formation of ^ J^^^^^^/^^^^ fhus 

 park withm the innermost preceding layer and outside the nej ""«, ^ ^^^,.^1 finds 

 fc"S a succession of concentric circles. The sap ejaborated by the lea^ ^ 



^if y. 1"^ a manner not as yet absolutely ascertained, mto the^«^« 9.^^^ 



S?i ^""^^"^ thin-walled ceUs connecting the wcod ^J;*^JJ^^J^f3 ^ ' a^e in layers, 

 ^d enlargezneit of which new cells (190) are formed. These ceflss^parat y^^^ 



^Jiemnero&s constituting the new ring of wood, and the outer ones 



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