THE SEEDLIXa FOLIAGE OF ULEX OALLTI 7 



about 23 per cent. Boodle sui^gested that this is a case of an 

 ancestral character [trifoliolate leaves] being favoured by ancestral 

 soil conditions, since the gorse plant may be supposed to be descended 

 from a plant with trifoliolate leaves, and having normal habitats among 

 richer soil than that usually frequented by gorse. 



To sum up what is known of the seedling foliage of U. europcdm : 

 a certain number of compound leaves usually occur after the cotyle- 

 dons and before the simple leaves, but they may be preceded or 

 interrupted by simple leaves, and in a few cases all the leaves are 

 simple. Seedlings grown on good soil produced an average of 10-79 

 compound leaves per plant, and those on sand an average of 8-27. 

 Compound leaves have also been found on older plants grown in 

 gardens on good soil, and on injured plants. 



Nothing appears to have been published as to the seedlings of 

 other species of JJlex. During Aug.-Sept. 1921 I was fortunate in 

 observing some thousands of seedlings of Z7. Q-allii on the Quantock 

 Hills, Somerset, where they had sprung up after heath fires which 

 had occurred in June. Five hundred seedlings were examined with 

 the following results. Seventeen (8-4 per cent.) bore simple leaves 

 only, and 483 (96"() per cent.) had one or more (up to 11) compound 

 leaves. The average number of compound leaves per plant was 2-6. 

 Of the compound leaves 79*6 per cent, were trifoliolate and 20-4 per 

 cent, bifoliolate, i. e. 4 trifoliolate leaves to each bifoliolate one. For 

 the purpose of these calculations tritid and bifid leaves have been 

 counted as " compound " ; as Boodle remarked with reference to 

 TT. europcBus, both bifoliolate and lobed leaves " may be regarded as 

 showing an 'attempt' to realize the ancestral trifoliolate type," and 

 it is therefore desirable for theoretical purposes to include the lobed 

 leaves among the "compound." 



No compound leaves were found after the sixth pair. The series 

 of uninterruptedly simple pairs commenced in 17 cases (3-4 per cent.) 

 immediately after the cotyledons ; in 330 cases (66 percent.) after 

 tlie first pair; in 94 (18*8 per cent.) after the second; in 23 

 (4-6 per cent.) after the third ; in 16 (3-2 percent.) after the fourth ; 

 in 15 (3 per cent) after the fifth ; and in 5 cases (1 per cent.) after 

 the sixth pair. The expressions "compound," "mixed," and "snnple " 

 pairs are used below to denote pairs composed respectively of two 

 compound leaves, a compound and a simple one, and two simple 

 leaves : — 



Percentages of compound, mixed, and simple pairs in tlie 

 first six pairs. 



Compound: {I) ^7-2- {2) l1-4^- {^) 4-2; (4) 4-4; (5) 1-8; (6) 0-2. 

 Mixed: (1) 8-8; (2) 10-0; (3) 5-4; (4) 2-8; (5) 2*2; (6) 0-8. 

 Simple : (1) 4*0; (2) 72-6; (3) 90-4; (4) 92-8; (o) 96-0; (6) 99-0. 



It will be observed that there is a regular reduction in the fre- 

 quency of compound pairs from the first to the sixth pair, except 

 that the fourth pair has 0*2 per cent, more than the third ; compound 

 pairs greatly predominate in the first pair, are frequent in the 



