THE LEAF. 



185 



a case is that cited by Masters of a rose-leaf of which 

 two of the leaflets " were brightly coloured like the 

 petals, the others being of their ordinary green colour." 

 Then there is the case given by Morren of an ex- 

 ceptionally large foliage-leaf of Oesnera Geroltiana 

 occupying the position of the inflorescence and being 

 at the same time brightly coloured. Thomas also 

 observed the partial transformation of a foliage-leaf, 

 on a purely vegetative shoot, into a petaloid organ 

 having the structure and colour of a normal petal, in 

 Rhododendron ferrugineum. 



5. Sporophyllopy op Foliage-leaves. — This also is 

 not of common occurrence. 



Blisgen describes more or less complete transforma- 

 tion of the leaflets of Mars ilia hirsuta into sporo- 

 carps (PI. XIII, fig. 3) ; in one leaf the lowest pair of 

 leaflets were in the form of closed fruits, the upper 

 pair in the form of mussel- shaped open bodies. 



The following phenomena may be included here, 

 although it is merely the foliage-leaf-like portion of 

 the sporophyll itself that is affected. In the different 

 species of the royal fern (Osmunda) transitional forms 

 between sterile and fertile pinna? of the frond con- 

 stantly occur ; e. g. in one pinna all the pinnules of 

 one side may be fertile, the other sterile ; in 0. rcgalis 

 certain portions of the frond which are normally 

 sterile may become fertile, or sporangia may occur on 

 all the pinnge of the frond, thus recalling the normal 

 condition of 0. jajjoniea in which sterile and fertile 

 fronds are quite distinct. 



The sterile portions of the fronds of Aneimia produce 

 sporangia on some of their segments occasionally. 



In the Ophioglossacese, also, certain segments of 

 the sterile portion of the sporophyll occasionally 

 produce sporangia. 



6. Staminody of Foliage-leaves.— A very remark- 

 able instance is recorded in Pimis sylvestris, in which 

 one or more pairs of needles on the short-shoots were 

 changed into stamens : an interesting transformation 



