ON ROCK PLANTS. 



297 



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. amoeiia and jP. subulafa, 



which are treated under " Spring- 



•Fig. 177. — Phyteuma 

 Charmelii. 



Bedding Plants." 



Phyteumas are charming plants for 

 sunny situations ; they are increased 

 by seeds or by division. F. Michelii 

 grows 6in. high, and bears heads of 

 reddish flowers during June and July. 

 P. orbiciilare 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 Chainnelii, 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 efl'ected 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 9in. high. P. 

 deiiticiLlata is a hand- 

 some species, thriving 



well in a light moist 

 soil. The leaves are 

 covered underneath 

 .with a white mealy 

 substance ; the flowers 

 are lilac, and are pro- 

 duced in large globular 

 heads on scapes up- 

 wards of I2in. high. Fig. 178.— Primula marginata. 

 Its variety cashmeriana 



is a splendid form, having violet-purple flowers with yellow 

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



