January, 1906.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



323 



portion of tin- perianth is tipped with a (int of pure 

 green, and tliis spot stands out in \i\id idiitrast to the 

 snowT wliitcness of the rest of the organ. For \vh;it 

 special purpose this conspieiious marking of green may 

 have been retained it is not easv to sav ; it is all sufli- 

 fient, hnux-\er, to show to the student tile leaf ancestrv 

 of the sepals and JH-lals. 



all of a green colour. If examined closely they are seen 

 to he nothing more than diminutive Iea\es, and they 

 even go so far as to retain the toothed edges which are 

 so familiar a feature of rose foliage. 



The change of the leaf into a coloured sepal or petal 

 is not, after all, very remarkable, for coloured leaf-like 

 org.ans, which really exhibit their character in e\erv 



A splendid South Anioricaii species with show \ bracts. 



\\\' can liiid at U'ast one exam|ile belonging to an 

 aihaneed laniily which has not found it ne<'essar}' to 

 produce any coloiu'ed sepals or pet.als for its flowers at 

 all. The (ireen Rose (Rusci 7'irii/is), a curious variety 

 ol the China Rose, is, as its name suggests, entirelv 

 without an\ coloured blooms. Vet this flower is 

 possessed of .1 number of sepals and petals, but they are 



resjx'ct exct'pt that thev are not green, are not at all 

 uncommon. One of the most striking plants exhibiting 

 this change of coloin" in the leaf is .1 South American 

 species, Boiigaiiri'illca glabra, specimens of which are 

 fairly often grown under glass in this country. The 

 real flower of the Boiigaiwillea is a small yellowish 

 blossom, of a much duller hue and nothing like the 



