POTTED FLOWERING PLANTS 339 



be placed in a cool cellar until the roots start. They should 

 then be brought into a light, airy house, and given an 

 abundance of water. All lilies need a frequent light fumi- 

 gation to prevent the attacks of the Aphis. 



CALLA LILIES 



512. Botanical classification. Order, Araceae ; genus, 

 Zantedeschia (after F. Zantedeschi, Italian botanist) ; 

 species: cethiopica, melanoleuca, albo-maculata and Elliot- 

 tiana. Some varieties are : 



Little Gem, dwarf, very free bloomer; Godefreyana, 

 medium in size, more prolific than type ; gigantea, plant 

 large and vigorous. 



513. Botanical characters. Callas are perennial herbs 

 with many long-petioled leaves rising from a thick rhizome. 

 The peduncle of the flower is as long or longer than the 

 leaves ; the spathe large, open, flaring, with a pointed, re- 

 curved tip. 



Habitat. Southern Africa. 



514. Propagation. Many small offsets form around 

 the parent rhizome of the calla lily, but they require the 

 growth of several years before they are large enough to 

 produce flowers. The parent rhizomes are long-lived, and 

 seem to improve with age. Yellow callas are now quite 

 popular as novelties or as ornamental conservatory plants. 

 They are difficult to propagate except from seed. Yellow 

 callas are grown in a similar way to white calla, but 

 seem to flourish best without a resting period. 



515. Culture. White calla is a valuable commercial 

 flower, and is grown quite extensively, although the in- 

 troduction of Lilium longiflorum and other species, as 

 all-the-year-round flowers, has lessened somewhat the de- 



