Occurrence of Folio i/e-leaves in Euscus androgynus. 131 



the leaves in question really belonged to the Euscus. In 

 ordinary descriptive language, they would be termed 

 " radical " (Plate IX. figs. 1 and 2). 



The occurrence of foliage-leaves in a plant so highly 

 specialised as Ruscus, where the leaf-functions are in 

 ordinary circumstances performed exclusively by expanded 

 cladodes, is of great interest ; and it can hardly be doubted 

 that if the development from seed were examined we 

 should find foliage-leaves constantly present, just as in 

 some other highly specialised forms we see a more general- 

 ised or ordinary development in the young state. For 

 example, the development of bipinnate leaves in the 

 seedlings of phyllodineous Acacias, wdiere in later life the 

 leaves are all developed as phyllodia ; of ternately com- 

 pound leaves in the seedling Furze (Ulex), where in 

 later life the leaves are simple and much reduced, the 

 leaf-function being mainly performed by the green branch- 

 thorns ; and of a few genuine foliage-leaves succeeding the 

 cotyledons in Sciadojntys., where in later life the leaf- 

 organs are all reduced to scales and the leaf-function is 

 performed by cladodial needles. To an evolutionist all 

 such cases are invested with what may be called an 

 archeeological interest, as affording indications of the kind 

 of ancestor from w'hich the more specialised form may 

 be supposed to have derived its origin. But, however 

 that may be, the traces here and there of the more 

 generalised structure alongside of the more specialised 

 are most important as links in the morphological series. 

 In the present case, I am inclined to consider the imme- 

 diate cause of the production of foliage-leaves to have 

 been the confinement of the plant in a flower-pot, with 

 consequent weakening of the aerial stems ; and, from the 

 propagation experiments I have made, I think that foliage- 

 leaves may almost always be expected from feeble rhizome- 

 cuttings. 



In these foliage-leaves, the blade is, as just mentioned, 

 ovate or lanceolate-ovate, and is somewhat acuminate. In 

 my largest example, the lamina is about 6 inches in length, 

 by about 3-| inches at its greatest breadth. In colour, 

 smooth surface, and dry leathery consistence, this lamina 

 closely resembles the cladodial expansion. A considerable 



