156 GARDEN FLOWERS. 



nials, generally hardy, remarkable for the colored bracts of 

 the involucre, which constitute the showy part of their in- 

 florescence. They are desirable among hardy herbaceous 

 subjects, the prevailing color being blue. They belong, in 

 truth, to the umbelliferous order, without having any ex- 

 ternal resemblance to that class of forms so familiar in the 

 Parsley, the Celer}', the Carrot, and the Fennel. They are 

 raised from seeds, which, like those of other perennials, may 

 be sown in May either in pots or in a bed. The young 

 plants, if nursed into strength, will bloom the following year; 

 but, usually, the old plants are the best if they are kept in 

 vigor. They are not very particular as to soil ; but a deep 

 sandy loam is best. 



E. Alpiniim (Alpine) ; hardy perennial ; 2 feet ; flower-heads 

 blue, in July ; Switzerland ; 1597. E. amethystinujn (ame- 

 thystine) ; hardy perennial ; 3 feet ; flower-heads blue, in July ; 

 Styria ; 1648. E. Boiirgati (Bourgati's) ; hardy perennial ; 2 

 feet; flower-heads blue, in July; south of France; 1731. E. 

 cceruleum (sky-blue) ; hardy perennial ; 2 feet ; flower-heads 

 blue, in July; Caspian; 18 16, E. giganteum (giant); hardy 

 perennial ; 4 feet ; flower-heads blue, in July ; Caucasus ; 1820. 

 E. planum (flat-leaved) ; hardy perennial ; 3 feet ; flower-heads 

 blue, in July ; Europe ; 1596. 



There are numerous other hardy perennial species. 



Erysimum. Hedge Mustard. [Cruciferae.] Hardy plants, 

 chiefly biennial, those which are cultivated being treated as 

 annuals : the majority are uninteresting objects. E. Pcroff- 

 skianum is, however, a very brilliant-fliowered plant, well 

 adapted for beds in gardens : indeed, there is hardly any 

 other plant which furnishes the color, — an intense orange. 

 It is perfectly hardy, and, if sown in the spring, will bloom 

 in June and July. It will bloom much earlier if sown in 

 pots like a half-hardy annual, and turned out in May ; for it 

 will then begin flowering in the pots in May. The plant is 



