ALPHABETICAL LIST OF PLANTS 357 



high, with large, fleshy, yellowish-green leaves, and flat, terminal 

 heads of rosy-pink flowers in August and September. There is also 

 a white form. 



S. spiiriufn. — Trailing species, with flat heads of handsome pink 

 or white flowers. There is an even better form, atrosanguineum^ 

 which has deep rosy red flowers. Both are very free-flowering and 

 handsome. 



S. testaceuni. — Has rather waxy-looking white flowers, borne in 

 flattish heads. One of the best. 



The above are a few of the best and most distinctive. 



Sempervivum (Crassulaceae), House Leek 



A genus belonging to the same order as the last. There are over 

 a hundred species, but many of them are either unsuitable or not 

 hardy. They are all of the easiest culture in any hot spot and in 

 any light soil. They are most useful for walls, growing readily in 

 any odd crevice. They are readily increased by division of the 

 offshoots. 



S. arachnoideum (Cobweb House Leek). — A most distinctive 

 species, the top of the rosettes being covered with innumerable fine 

 threads, stretching from point to point, looking exactly like a spider's 

 web, from which it gets its popular name of " Cobweb House Leek." 

 Spikes of handsome rose-coloured flowers appear in the summer. 

 It is a most charming and attractive plant, and should be grown in 

 large patches in some dry and hot spot. 



S. a. Laggeri. — Is a larger form of the above. 



S. ciliatiwi. — The margins of the leaves are fringed with trans- 

 parent, hair4ike bodies. Flowers, in close, flat heads, are a good 

 yellow colour. A hot and dry spot. 



5. doellianum. — Rosettes rather hairy, with tips connected by 

 a few cobwebby threads. Flat heads of bright red flowers, in dense 

 panicles 4 to 6 inches high, 



S. rubicundum. — The leaves are bright orange, tipped with 

 green ; very distinct. 



Other varieties are : 6*. ai vernense^ S. Tectorum^ S. calcareum^ 

 S. globiferuni^ S. piliferum^ and many others. 



Senecio (Compositae), Grounsel, Ragweed 



A large genus of over one thousand species, but only a few are 

 suitable, being mostly too coarse-growing. They are all of easy 

 culture in any loamy soil, and readily increased by seed, division, or 

 cuttings. The following are a selection of the best : — 



S. aicrantiaciis (syn. Cineraria aurantiacus). — Sunny, sheltered 



