354 ROCK GARDENS 



more like S. Frederici-Augusti than any other, but there is some 

 confusion about it. It is a rare species. Of vigorous habit. 



S. toniheanensis {Group I 11.^ Cushion). — Very like 6". diapen- 

 sioidesy but not as good. Its rosettes are rather more spiny, and 

 leaves devoid of silver markings. Flowers white. 



6". trifurcata {Group /., Mossy). — Has rather distinctive foliage, 

 its leaves being rather like stags' horns. It is of vigorous growth, 

 and quickly makes large tufts. The panicles of flowers, which 

 are white and of a good size, are borne on slender stems about 

 6 inches high, and in such profusion as to hide the plant. Of the 

 easiest culture, and quite one of the best of the mossy Saxifrages. 

 S. ceratophylla is a variety of this species. 



S. triternata {Group II.., Encrusted). — Of the Aizoon type, form- 

 ing small rosettes, and bearing heads of lovely rose-pink flowers. 



S. umbrosa, ^''London Pride.'' — This well-known Saxifrage needs 

 no description. It is quite indifferent to position, growing well 

 under trees, and making a fine show in summer, with its airy spikes 

 of white flowers dotted with crimson. 



S. valdensis {Group II., Encrusted). — So very closely allied to 

 5. cochlearis that it may be considered but a small variety of it. 

 A very attractive plant, of easy culture, and will do in a position not 

 fully exposed to the sun. 



S. Vandellii {Group III.., Cushion). — Forms very hard, dense tufts 

 of spiny grey leaves, quite devoid of any trace of silvery markings. 

 The flowers are pure white, and borne several on a head on stems 

 3 to 4 inches high. It is doubtful if this species likes lime. 



S. Wallacei (see S. Camposii). 



S. Wulfeniana {Group /K, Creeping). — Very akin to, if not a 

 variety of, S. retusa. 



S. Zimmeteri. — A hybrid between S. Aizoon and S. cuneifolia. 

 Small rosettes of dark glossy green leaves, and white flowers in 

 loose clusters. 



The above fairly represent the best species. There are, however, 

 many more, but either not sufficiently distinct or attractive enough 

 to call for special notice. 



ScABiosA (Dipsaceae), Scabious 



A genus of the Compositae order, not of much value for the rock 

 garden, being mostly too coarse-growing. The following are the 

 best species : — 



S. alpina (see Cephalaria alpina). 



S. caucasica. — Grows about I2 inches high, and has flower-heads 

 of a pale blue colour. Blooms from June to August. It is of the 

 easiest culture in any soil. 



