ON ROCK PLANTS. 



297 



Fig. 177. — Phyteuma 

 Charmelii. 



ift! high; the flowers are bright yellow, very fragrant, and are 



produced from May to August. 

 Phlox is a genus yielding several dwarf perennial species 



suitable for the rock garden, such as P. amcena and P. subulata, 



which are treated under " Spring- 

 Bedding Plants." 



Phyteumas are charming plants for 

 sunny situations; they are increased 

 by seeds or by division. P. Michelii 

 grows 6in. high, and bears heads of 

 reddish flowers during June and July. 

 P. orbiculare grows ift. high, and 

 produces violet-purple flowers, in 

 spherical heads, from June to August. 

 P. Scheuchzeri produces blue flowers 

 in May, and grows from 6in. to i2in. 

 high ; its variety Charmelii, generally 

 known as P. Charmelii (Fig. 177), 

 also has blue flowers, in round heads, 

 and is an excellent plant for a well-drained position on the rockery. 



Primula is an extensive genus of alpine perennials, con- 

 taining many species 

 suitable for rock-garden 

 culture. Propagation is 

 usually effected by 

 seeds, though some- 

 times the old plants 

 may be carefully di- 

 vided. P. cortusoides 

 produces umbels of 

 rose-coloured flowers 

 during May; the scapes 

 are <pin. high. P. 



i denticulata is a hand- 



i some species, thriving 



: well in a light moist 



1 soil. The leaves are 



i covered underneath 



i with a white mealy 



- substance ; the flowers 



I are lilac, and are pro- 



1 duced in large globular 



jheads on scapes up- 

 wards of 12b. high. 



' Its variety cashmeriana 



\}s a splendid form, having violet-purple flowers with yellow 



'eyes. P. floribunda has small golden-yellow flowers produced 



Fig. 178. — Primula marginata. 



