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THE AMERICAN NATURALIST [Vol. XLI 



stage, the "very similar" western Clematis ligusticifolia goes 

 further, and, by the deepening of the notches in the terminal 

 leaflet, becomes pinnate with five leaflets. Many other species 

 of Clematis, including some w'hich are commonly cultivated, have 

 pinnate leaves. 



In the poison iYy, Rhm toxicodendron, simple leaves are occasion- 

 ally found, but the typical form, is tern ate. Many leaves exhibit 

 both basipetal and basifugal features (P'ig. 2a), and explain the 

 occurrence of both palmate and pinnate leaves in this species 

 (Figs. 2b and 2c). 



An interesting comj)aris()n may nindc^ between the leaves of 

 the black rasi)berry, Rrdrm occidt'nl(i/is, and llic w ild red raspberry, 

 Ruhiui stricjoHus. In the former, I-'ias. ;ia and .'!b, the basipetal 

 tendency predominates, leading to ])cdate leaves; a basifugal 

 notching of the terminal leaflet is, however, often observed. In 

 the closely related red raspberry basifugal growth leads to pinnate 

 leaves, Figs. 4a and Ah, but basipetal lobation may be seen in the 

 basal leaflets. 



The t'onn of leaf shown in Figs. Id, 2a, .'Ja, and 4a U seen also 

 in Fio-. oa from Xniumh (urmidvs. In the pinnate leaves of this 

 species there may be a l)aval secondary leaflet, as shown in Fig. 

 5b. Such evi<leiu<> cf baMpctal growth in pinnate leaves is often 

 found. It appears in tlie long leaves of Ailanthm c/lamhdosus 

 (Fig. Gb). In the seedling of this species, ternate leaves with 

 basal notches have been drawn })y Jackson,^ from whose paper 

 Fig. (la has been taken, 'rhus it is evident that the basipetal 

 and basifugal directions of growth are present together in a great 

 variety of leaves. 



The relation of the basipetal secondary leaflets to twice pinnate 

 lea\'es is shown in Figs. 7, 8, and 0. In the elder, Sambticus 

 canadensis, \\w basffngal development of ])rimary leaflets is shown 



