55 



rate of leaf expansior, a -••-.r'-D v-^ -: •-; -Kr rl->y+:j -rnnat y' -nc lo-fp 



light radiation. This interpretation is not to be regarded as 

 at all well established, but it is at least a suggestion of one 

 •way in \vhiGh the external 3onri i -^ ^ "->. rf light ' i- -^ « --i ci • ^ .r ;vn ' 

 duration may be registered in such plants as were :ie re employed, 



Trends of the plant v lues and their se.i^.gonal ranges 

 f or the varioas stat'ons. 



""'■e fo!lk)v-ing o nsifler--) ti nn r-f-' th --^ seasonal marches of 

 the i:-Y.'eek plant values ior the various stations will be limit- 

 ed in extent, since most of the facts and deductions that seem 

 to be of i "-nortivir;.-! • r, •*-his connection can be befitpr ''r,■rr^^.^'f 

 out later. Attention v;ill here be called only to two generali- 

 zations regarding the plant grap' s: (1) The plant graphs be- 

 :'■ - -.-if-.', "alues of e.'^or.f. I'^n, r'se to hif^h midsurr'"^ f-"'" -'alues and 

 then fall to low values .it tiie end of the season, (2) Differ- 

 ences in the magnitudes of the midsummer maxima constitute the 

 chief discre'na:'!''^ i ;= ^> ^, e'*"'vfle'''' ^'^^^ graphs for the -/srions ^f''''ions, 



Oakland siiows lower values of the stem height and leaf- 

 product than any other station owing largely to the low values 

 §f thfl ■f"err::^eratT)re th. ■•■ -r, r^v*. i1 .-^--l .-'■♦- fhis of --^ i ,-,r ^.'■irnr. p-hn.-i*: 



the season. The Jata ' ' 's stu.ly indicate in all cases f 

 the climate of Oak:" o far as it affects the plants 



lite that of B.'ny o"' thp "jth.^r sta"*"' '>'.;-■ p ir-r,l o-7p i . ■R'-'-'- 

 graphs for this station, show the, typical low values at the be- 

 ginning and end of the season, however, with midsummer maxima 

 of 124 for the stem .x^.^^,. ,.....,. ^^ :or the lecr..I-..r.vi act . Ji.t, - 

 "ille shows tj^pical graphs, the highest value reached by the 

 stem hei-ht being _.14P) and by the leaf-product 139. The end of 



'6 S e u .-i V.' Xi ctt this bL J liiix ci'J tuij i; ►j'j. ij ■■; „ ., 



