50 L'liln rsil jj oj Calijornia J 'iib Lea I ions in Botanij ! '^'"'- ' 



At this lime llic youii^ flower-luul averages 2 to 8 iiiin. in Icngtli, the 

 size of the 1)11(1 and the (h'gi-ce of (h'V('h)i)ni('ii1 a|i|)ai-cii1 ly varxiiig 

 considerably, according to llic strength of Ilic planl. The aiillici's by 

 this date practically fill llic iiitcrioi- of llic Howcr-lmd. In general 

 the second bud in llie "crown" — llic first, as noted above, being func- 

 tionless — is the largest and most highly differentiated, each successive 

 bud thereafter being two weeks or more behind its immediate pre- 

 decessor. 



What appears to be the critical period in development at which 

 the ajiex of the rootstock ceases to grow and llic buds nearest it are 

 arrested in their development occurs late in May. Buds seem to 

 gather momentum in their development, so that those which have their 

 ])i-imordia well advanced before this critical period go on developing, 

 while in the case of those which are not sufficiently advanced further 

 development is suspended until the following year. As has been stated 

 above, when the development of a bud which has formed its primordia 

 is sharply arrested the result is usually fatal, still younger buds (fig. 1, 

 &'o) not so M^ell differentiated are usually able to resume growth upon 

 the arrival of the next active season. Small plants that form only 

 two buds and send up one shoot a year thus lay down their buds nearly 

 two years in advance. On the other hand, those plants which send 

 up four or more shoots a year begin to form some of their buds one 

 season and the others two seasons before they are to appear above 

 ground. 



In June and July, following the period of suspended activity, the 

 entire terminal bud of the rootstock, or crown, is growing with maxi- 

 mum rapidity. All parts are increasing rapidly in size at this time, 

 but most noticeable is the renewed activity of the young foliage leaves. 

 They increase in size more rapidly than the young flower-buds and 

 overtop them by the latter part of July (pi. 7, figs. 4 and 7). There 

 is still a striking inequality in size and in degree of development among 

 the various buds, but by the middle of July, or earlier, the youngest 

 or innermost bud for next season is larger and better differentiated 

 than the oldest or outermost was in May. Sometimes when only two 

 buds are developing for next season they are nearly ecpial in size 

 and in degree of differentiation, and when the outermost — usually 

 functionless — bud (cf. fig. 1, />,) develoi)S in addition to the otlicrs it 

 is very likely to be smaller than its imniediate successoi'. It seems 

 that the checking of development of a bud as far advanced as this 

 outermost bud always is at the critical period has a niueli more per- 



