240 ME. I. H. BURKILL ON SOME VARIATIONS IN 
two branches are present each with only one flower (bin the 
diagram), the lower shows itself stronger in producing more 
earpels: when the inflorescence is more vigorous, the upper 
branch and not the lower takes the lead, producing 2 to many 
flowers; but these, as a rule, carry fewer carpels than the 
terminal flower of the lower branch. 
TaBLe XVII. 
Number of Carpels in Flowers of Thalictrum flavum according to 
Position on Braneh. 
Average | Average | Average 
no. of | no. of | no. of 
carpels | carpels | carpels 
No. of in in in 
cases. | terminal] terminal) lateral 
flower of | flower of flowers ofl 
lower | upper | upper 
branch. | branch. | branch. 
One branch only developed (c) ...... 30 8'8 
Upper branch unbranched (2)......... 44 9:86 | 8:02 
» »  2-flowered ............... 4 1075 | 9:0 8:25 
» s. Š y, eo 6 1033 | 65 8:67 
» » 4 » (a) ....... 1 11:0 8-0 1:67 
» » O 19 eene ntes 4 10:0 8:0 9°75 
» » 6 99 C seesseassssssasa 1 90 |Aborted. 8:0 
5» 00» E 2 115 | 75 10:0 
This Table shows that the more vigorous (in number of flowers) 
the upper branch, the more carpels does the lower branch bear; 
and so the number of carpels is affected by the strength of the 
axil from which arise the flowers containing them. The lower 
branch does not itself branch so readily as the upper. When 
this upper branch carries many flowers, the terminal flower 
carries fewer carpels than the lateral flowers. 
_ In plants which have usually three branches in the axil 
instead of two, as is sometimes the case, the results are similar. 
The plants examined were gathered in Waterbeach Fen, near 
Cambridge, in July. 
