THE SEEDLlXd FOLIAGE OF ULEX OALLTI 9 



Sl-3 per rent. Imve the first pair 8 + 3. Thns there is a g^reater 

 ])robability that the tirst pair will be 34-3 if conipouiid leaves oeciir 

 in siibsecpient pairs. 



Taking the tirst six pairs together, tlie relative frequency of the 

 various compound and mixed types is as follows : — 



3-1-3 (00-7 per cent.) ; 3 + 2 (12-3 per cent.) ; 3 + 1 (8-4 percent.) ; 

 2 + 2 ((3-1 percent.) ; 2 -h 1 (ll'H per cent.) ; in threes (Ov per cent.). 



The pairs (3 + 2, 3 + 1) composed of one trifoliolate and one 

 reduced leaf account for 207 per cent., while those composed of two 

 reduced leaves (2 + 2, 2-t-l) account for 17*9 per cent. Of the 

 pairs in which reduction has taken place the anisomerous ones (3 + 2, 

 3-1-1. 2 + 1) account for 32-5 per cent, and the isomerous (2 + 2) for 

 only G'l per cent., anisomerous reduction being more than five times 

 as frequent as isomerous. The two leaves of a pair pass through the 

 intermediate (bifoliolate) stage of reduction concurrently in only 

 15-7 per cent, of all cases. 



The 500 seedlings examined are referable to 72 different types 

 according to the arrangement of trifoliolate, bifoliolate, and simjjle 

 leaves preceding the continuously simple series. These types may 

 be expressed by formula; in which each leaf of a pair (or whorl of 

 three) is represented by the number of its leaflets, or if simple by the 

 tigui-e 1, successive pairs being separated by a semicolon. Thus the 

 formula 3 + 2 ; 2 + 1 denotes a seedling in Avhich the leaves of the 

 fii'st pair are trifoliolate and bifoliolate respectively, those of the 

 second pair bifoliolate and simple, and all the subsequent leaves 

 simple. 



Out of 72 tvpes 53 occur once only, 5 twice, 2 three times, and 

 1 four times. 127 seedlings out of 500 (85-1 per cent.) belong to 

 the remaining 11 types, which occur respectively from 8 to 241 times. 

 These relatively common types have not more than two pre-simple 

 pairs, and are as follows in order of frequency : — 



3 + 3 (244 seedlings). 3 + 2(34). 3 + 3; 3 + 3(25). 



3 + 3:2 + 1(28) 3 + 1(17). 2 + 1(17). 1+1(17). 2 + 2(15). 



3 + 3; 3 + 1 (15). 3 + 3; 3^-2(12). 3 + 3; 2 + 2 (8). 



It will be noticed that in these common types, where two pairs 

 of leaves are compound or mixed, the total number of leaflets of the 

 second pair is either equal to or less than that of the first. Such types 

 may be known as " mireversed," a " reversed " type being one in which 

 the^ total number of leaflets in any pair exceeds that of the preceding 

 pair. As has been stated, all the leaves are simple in 3-4 per cent, 

 of all cases, and the remaining 9G-6 per cent, is composed as to 88-2 

 per cent, of " unreversed " and as to 8-4 per cent, of " reversed " types. 

 The greater the number of pairs preceding the continuously simple 

 leave"^, the more frequent are the "reversed" types. Thus of seed- 

 lino-s with 2 pre-simple paii-s 5-3 percent, are " reversed," wnth 3 pairs 

 47 -l^ per cent., with 4 pairs 68-8, with 5 pairs 73-3, and with 6 pairs 

 80 per cent. The reversal " trough " is in the second pair in 45-1 

 per cent, of cases, in the third in 35-3 percent., and in the flrst pair in 

 10-0 per cent. Out of 42 seedlings of " reversed " type, the reversal 



