8 TTTE JOUKNAI. OF liOT AXV 



secoiid, and few in the following pairs, Tlie mixed pairs are fairly 

 frequent in the hrst and second pairs, and gradually decrease in 

 the remaining ones from a maximum of 10 per cent, in the second 

 pair. Simple pairs are few in the first pair, and greatly pre- 

 dominate in the remainder, rising to a maximum in the sixth pair : — 



Percentages of trifoliolate, hifoliolate, compound and simple 

 leaves in the first six p)airs. 



Trifoliolate: {1)^1-^; (2)l^-Z;{^) 2-9; (4) 2-9; (o) l-o;(6) 0-3. 

 Bifoliolate: (l) 9-9; (2) 8-1; (8) 4-0; (4) 2-9; (5) 1-4; (G) 0■l^. 

 Compound: (1) 91-G; (2) 22-4; (8) 6-9;(4) 5-8; (5) 2-9; (0) 0(1 

 Simple: (I) 8-4; (2) 77-G; (3) 93-1 ; (4) 94-2; (5) 97-1 ; (G) 99-4. 



It will 1)3 noticed that the percentages of compound leaves; and 

 of trifoliolatu and bif(diolate leaves separately, regularly decrease from 

 a maximuiu in the first pair. Trifoliolate leaves are commoner than 

 bit-'oliolate in the first two pairs; hifoliolate are commoner than tri- 

 foliolate in the third pair ; and the two types of compound leaves are 

 efpiilly common in the remaining pairs. Simple leaves are compara-. 

 tivelvfew in the first pair, being less numei-ous than hifoliolate ones ; 

 froni the second pair onwards they greatly predominate. 



In th3 following table each type of pair (or whorl of three leaves) 

 is expressed by a foruiula in which each leaf is represented by the 

 number of its leaflets, or, if simple, by the figure I. Thus the 

 formula 3 + 2-1-1, for example, represents a whorl of three leaves — one 

 trifoliobite, one hifoliolate, and the third simple : — 



Percentages of various ti/pes of pairs (or threes) in the first 

 six pairs (or threes). 



3 + 3 + 3: (1) 02. 

 3+3 + 2: (1)0-2. 

 3-L-2 + 1: (1) 0-4. 

 3 + 1 + 1: (1) 0; (2)0-2. 



It will be observed that the four types (3 + 3, 3 + 2, 3 + 1, 2 + 2) 

 in which there is no reduction or a reduction of 1-2 leaflets are 

 commonest in the first pair. The type (2 + 1) in which three leaflets 

 are unrepresented is commonest in the second (G pei- cent.) and third 

 (4-2 per cent.) pairs. 3 + 3 is the commonest compound or mixed 

 type in the first and second pairs, but in the third pair the arrange- 

 ment 2 + 1 is 2-G times as frequent. 



Out of the 330 cases in which only tlie first pair is compound or 

 mixed 241 or 73-9 per cent, are of the type 3 + 3 ; out of 153 cases 

 in which one or more subsequent pairs are compound or mixed 129 or 



