THE LILY FAMILY. 



163 



Allied to Asparagus is the curious genus Ruscus, of which 

 Butcher's Broom (^R. aculeatus, R. Hypophyllum^R.Hypoglos- 

 sum^ R. racemosus, and R. androgynus) are examples. The first 

 four being caespitose shrubs 1—3 feet in height and natives 

 of Europe — the latter being a climber from the Canary 

 Islands. In all the leaves are alternate, elliptical, acuminate, 

 and persistent. Their flowers are small, monoecious, or 

 dioecious ; in the three first named species they are borne on 

 the disc of the leaves, and in R. androgynus on the margin 

 analogous to Xylophylla {see p. 33). This singular mode of 

 flowering has led some botanists to consider the so-called 

 leaves, branches, but on noting their regular alternate evolu- 

 tion, definite size, form, and texture, in conjunction with 

 the fact that R. racemosus produces its flowers in terminal 

 racemes, quite free from the foliage, I am led to think that 

 they are true leaves, having (R. racemosus excepted) the 

 floral peduncle adnate, or amalgamated with the midrib of 

 the leaf, as is the case with Erythrochiton hypophyllanthus 

 and Turnera ulmifolia^ hothouse plants. Ruscus racemosus 

 is known as the Alexandrian Laurel. 



Allied to Liliacege is a small family of aquatic plants — 

 Pontederacese — consisting of about 30 species, widely dis- 

 tributed, but possessing no special economic uses. JPontederia 

 cordata, a native of N. America, is a neat plant, with heart- 

 shaped leaves and a spike of pretty blue flowers. It is per- 

 fectly hardy in this country. P. coerulea is a singular plant 

 from the W. Indies and tropical America, having roundish 

 heart-shaped leaves borne on a thick, swollen petiole full of 

 air-cells, by which the plant floats on the surface of the 

 water. It produces offsets freely, soon extending itself over 

 a large surface. It rarely flowers in this state, but when it 

 becomes attached to the soil its footstalks become long and 

 narrow, and it then produces its pretty blue flowers. 



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