STOKKS AGRICULTURAL EXPERIMKNT STATION. 321 



in a cduJensed condition. Tlie biul-scalcs are nioditied leaves «'liieli 

 proteet tlie jjarts ^Yitllin from nieelianical injury' and from loss 

 of iiioi,stnre, but are of little value as a protection against cold as 

 is olleu supposed. At falling tliey leave a ring or l)and of scnle- 

 scars marking the limit of each year's growth. Tliese Ijauds id'ten 

 remain distinct for many years (see tuig of IJeeeh j). l"*!.)) 

 and ]jy counting their number the age of the brancblet may be 

 estinuited. Thus it can jjc readily seen that the ligure ot the 

 Horse-chestnut represents growth made during three years, l^^ach 

 vear a ring of new wood is formed just underneath the liark, and a 

 count of the nundjer of these annual rinj/s between tbe central pitli 

 and the bark, as seen in a ci'uss section of a lirainh or trunks 

 will likewise give the age of the part investigated. Tlie uppermost 

 buds of a year's growth are generally the largest and most likely 

 to develop into branches the followiitg spring. In s:niie species, 

 sttch as many ot the Evergreens, and the Carolina I'oplar (p. o!)5) 

 for example, the l)ranches coming from these more \igorotts littds 

 form regttlar "\\horls along the trunk at the tipper jiart ot each 

 year's growth and afford for such species a tliird means of esti- 

 mating the age. Certain of the buds do not eontinue the growth 

 of the twig but form flowers which de\elop into fruit. AVhere tlie 

 indi\'idual trtiit (in the llorse-cliestnut the fruit cluster) Has 

 attached, a fiail-scar is left and these fruit-scars furnish evidence 

 of the amount of fruit produced in pre\i(nis years. 



In some species, such as the Black Tirch (p. -ilo) and the 

 cultivated Cherry (p. .lOS), a sharjj distinction can be di'awn 

 between rapidly-grown long shoots which have elongated inter- 

 itodes and continue the growth of the twig and slowly grown 

 short spurs which have greatly abbreviated internodes and crowded 

 leaf -sears. The frnit-spurs of the Apple (p. dyT) and I'ear 

 (p. 485) are of this latter type. 



Of the distinctive characters gi\en under the heading twigs may 

 be mentioned the relative thickness, whether stout or slender, the 

 presence or ab.sence ot thorns or prickles, ihe cobu', the taste as 

 indicated under the discussion of the liark, and the character of 

 the surface, whether smooth or moi-e or less covered with hairs. 

 Twigs are called hairy when the hairs ai-e individually distinct, 

 downv when thev are fine and numerous, and woolly or cottony 



