38 



BUDS ON LEAVES. 



length from the base. It there terminates in a bud, or, if it divides, in several 

 buds, and inasmuch as these are flower-buds, it may be looked upon as a flower- 

 stalk. These buds cannot therefore be said to be epiphyllous, i.e. to spring direct 

 from the tissue of a foliage-leaf. In reality each is borne upon a structure of 

 the nature of a stem, only the peduncle, stalk, or axis has partially coalesced with 

 the midrib of a leaf. Willdenow, who was the first to describe it, named the plant, 

 represented in fig. 198, the Butcher's-broom Helwingia (Helwingia rusciflora), 



/^-^^ 



Fig. 198.— Helwingia rusciflora, with flowers seated upon the foliage-leaves. 



because the floral buds here as in the Butcher's-broom (Ruscus) were borne by 

 foliaceous structures (cf. vol. i. p. 333). The two cases are, however, essentially 

 diflferent. The green leaf -like structures in the Butcher's-broom, which carry floral 

 buds upon their upper surfaces, are not leaves at all, but leaf-like shoots, that is 

 to say axes, and the buds upon them are, therefore, not epiphyllous but cauline. 

 The same statement applies, of course, to other plants with flat, expanded shoots, 

 a few representatives of which are shown in the illustration of p. 335 of the first 

 volume, and in this category must be included Ferns also, if we look upon their 

 fronds as phylloclades, and not as foliage-leaves. It would be quite out of place 

 here to enter into the question of the nature of fern-fronds, or to set forth the 

 reasons why they must be considered as phylloclades. The proof cannot be 



