258 VEGETABLE ORGANOGRAPHY. 



themselves may present the same division, and the leaf 

 is then said to be Tripinnatifid, &c.; but beyond a 

 double division it is rarely that the trouble is taken to 

 examine the regular system, and under the names of 

 MuLTiFiD, Laciniated, Decompound, or Dissected, 

 are confounded all leaves with numerous and indefinitely 

 divided lobes. 



The same theory may be applied to all palminerved 

 or peltinerved leaves, with this single difference, that 

 one applies to the principal nerves of these leaves all 

 that is said of the secondary nerves of penninerved ones. 

 Thus, in these palmi- or peltinerved leaves, the lobes 

 are the expansions of each of the nerves which arise 

 from the top of the petiole, and the leaf is said to 

 be Palmatifid or Peltifid, when the lobes are united 

 halfway; Palmatipartite or Peltipartite, when 

 they are only so near the base ; Palmatisected or 

 Pedatisected, when they are not at all. 



As for pedalinerved leaves, the secondary nerves are 

 those which, as in penninerved ones, give origin to lobes 

 more or less united together. 



Thus, in all the classes of leaves with ramifying or 

 angular nerves, it is the unequal uniting together of the 

 lobes which causes the divisions; and the union of the ex- 

 tremities of the fibrils, which, by its inequality, produces 

 the teeth ; and it is so true that these facts ought to be 

 referred to the more or less considerable development of 

 the parenchyma, that in several kinds of plants the 

 divisions are seen to vary in depth according to the varied 

 action of the causes which make the fibres elongate or the 

 parenchyma to be developed ; thus, a nourishment very 

 watery,and but little endowed with nutritive matter, causes 

 the fibres to elongate, without the parenchyma being suf- 

 ficiently developed, as we see in several aquatic plants, 

 and especially in Ranunculus aquatiUs. A small quantity 



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