2oH r iiin rslh/ of (\ilifor)il(i I'lihllrafioiia i)i Botanii [Vol.7 



(if phiiils t'lniiish the dala on the liasis of wliicli ;i ('crUnii |)('i'ct'iita<i(' 

 nihlici- coiilciit is assi<iiic(l 1o a ^ivcii iiHlivi<liial. Fij»iii'(' 4 sliows 

 plants trinmicd for liriiidiii^' and analysis and it is ajiparent that 

 what is h'ft of the |)hiuts I'cprescnt areas i-ou<^hly ('(luivah'nt to the 

 portion lictwccn 1 and '1 in Haui'c '). 



It appiars from tal»hs 7 and S tliat inaxinium (piantitics of rnlil)i'r 

 occur at the soil line. In the ease of futni'e examinations of plants to 

 li'd at the per cent of contained rulihei' it would appear that this 

 hasal poi'tion of the nuun ti'unk alone iiiijiht funnsh a characteristic 

 sample and that the whole ai'(>a between 1 and :{ ( ti^-. .") ) need not 

 he handled. In other words analysis of a soil line sanijile of such a 

 plaid as 620 (table 7, 620 (5) ) indicated that approximately 3 per cent 

 of rubber was ])resent and it is held that this fi<:ui'e uuiy safely be 

 taken as a fair a])proximation of the per cent borne liy the entire ])lant 

 exclusive of the I'oot and the shoots and twig's less than three or four 

 years old. At first sijiht it would appear that this figure is too high 

 since table 7 indicates that an average percentage content of segments 

 (o) to (13) of 620 would ajiproximate 2 rather than 3 per cent. In 

 this connection, however, the relative weights of the areas between 

 1 and 2 (cf. fig. o) and between 2 and 3 must be taken into account. 

 A lunnber of weighings indicate that the weight of that portion 

 between 2 and 3 is approximately 30 per cent of the total weight of 

 the region between 1 and 3. This total weight will roughly approxi- 

 mate 1500 grams. It appears from the data given that if the mai)i 

 trunk bears in the neighborhood of 3 per cent the branches up to 

 the limits of the three to four year old wood will bear about 2 per cent. 

 With this assumption in mind the following relation ajipears to hold 

 good : 



Wcifrlit 1 to 2 = n.in gm., -which at 3% = 34..")0 gm. rublicr. 

 Wciglit 2 to 3 = 4."iO gni., wliit'h at 2% =^ 9.00 gni. rubber. 



Total wciglit = l.")00 gm., total rubber = 43.50 gin. 

 Total weight = l.'OO gm. at 3% =; 4.5.00 gm. rubber. 

 Total weight = I.jOO gm. at 2% = 30.00 gm. rubber. 



Based upon such rotigh estimates as these it seems clear that, due 

 to the greater weight of the main trunk as compared with the older 

 blanches, a report of per cent of contained ridiber based upon an 

 analysis of portions of the i)lant near the soil line would not give a 

 wholly errone()ns estimate of the amount of rubber to be obtained 

 fi'om a plant harvested so that jiarts from 1 to 3 (tig. .")) alone were 

 I'etaiucd. 



