NOMENCLATURE. 



each of the two that are below it (germmatio imbricativay in 

 SaHsburia adiantifoha. Tab. IV. Fig. 7.), or they he riding 

 upon each other (G. equitativa, in the Common Ash, Tab. IV. 

 Fig. 5.) The leaves always lie curled up in the buds, as in 

 the Elder (Tab. IV. Fig. 2.), and in the Snowball (Tab. IV. 

 Fig. 8.) 



74 



' The buds are either leaf-buds {gemma, foliifera)^ when no- 

 thing but leaves and leafy shoots spring from them ; or they 

 are fruit-buds {gemma, fructvferd)^ which produce both blos- 

 soms and fruit. 



There is also a remarkable difference in the situation of 

 the parts which are included in a bud, (304.) 



75. 



A leaf (folium J is a green surface, which, for the most part, 

 is spread out horizontally. 



Leaf-stalk {petiolus) is the part by which the leaf is joined to 

 the stem or branches. There are transitions from the leaf-stalk 

 to the leaves, when the latter are abortive, and then the leaf- 

 stalks assume the form of leaves. With De Candolle, we 

 may call these intermediate forms phyllodia. They are seen 

 most distinctly in the Acaciae from New Holland, and in 

 Phyllanthus, (Tab. III. Fig. 1.) We even suspect, that 

 what are called leaves in Bupleurum, are nothing else but 

 such intermediate forms. 



Transitions from leaves to roots are also observed in water 

 plants, when the undermost leaves are much subdivided in 

 the form of hairs, and thus resemble roots. We observe this 

 in the Ranunculus of our streams, in Sium latifolium, in Nec- 

 tris aquatica, and many others. 



76. 



The axis {axilla), is the angle which a leaf or leaf-stalk 

 forms at its insertion with the stem or branches. Jxillaris 

 thus denotes that which springs from the axis of the leaves. 



