318 



SYSTEMATIC BOTANY. 



Echium, L. 

 Borago, Tournef. 



ILLUSTRATIVE GENERA. 



Symphytum, L. 

 An ch usa, Z. 



Lithospermum, L. 

 Myosotis, L. 



Affinities, &c. The floral formula isS5|P5A5G2. The 4-lobed 



o\ary and fruit of this Order agree exactly 

 with those of the Labiatae, in which the ir- 

 regular corolla, didynamous stamens, opposite 

 leaves, and square stems differ widely. This 

 character of the ovary does not occur in any 

 other regular o-androus gamopetalous Order. 

 The Nolanaceae and Ehretiaceae depart from the 

 general type of this Order. Ehretiaceae seem 

 to bear the same relation to the proper Bora- 

 ginaceaB as the Verbenaceae to Labiatas, having 

 confluent carpels, terminal styles, and a shrubby 

 or arborescent habit. The corolla mostly pre- 

 sents a coronet of scales in the throat, which 

 some incline to regard as abortive stamens. The 

 bractless inflorescence of some of the genera 

 is remarkable. The inflorescence, whether 

 with or without bracts, is probably a unipa- 

 rous scorpioid cyme, though it has been con- 

 sidered to be an inflorescence of " parti- 

 tion." 



Fig. 417. 



Bcorpioid cyme of Myosotis 

 palustris. 



Distribution. A large Order, the species of which are mostly natives of 

 temperate climates in the northern hemisphere. 



Qualities and Uses. The plants of this Order, remarkable for their rough 

 foliage, have a reputation as mucilaginous and cooling herbs. Their chief 

 importance lies in the dye furnished by the roots of Ancliusa linctoria 

 (Alkanet) and various species of Echmm, Onosma, c., and the beauty of 

 their flowers, whence the genera above cited include many common 

 garden plants. The Forget-me-not is a native species of the genus Myo- 

 sotis. Many Boraginaceaa occur wild with us. 



EHRETIACEJG consist of a group of plants included in Boraginaceaa 

 by Bentham and Hooker, but separated by some authors on account of 

 the coherence of the carpels and the terminal style (which is gynobasic 

 in true BoraginaceaB) and a drupaceous fruit. Some genera have peri- 

 sperm, others not. They seem to be as distinct here as Verbenaceae from 

 the Labiatse ; but the agreement is very close at some points in both cases. 

 They are also nearly related to the Cordiacea? ; but the latter have twisted 

 aestivation and plaited cotyledons. Most of them are tropical trees or 

 shrubs. None are of much importance : the drupes of some Ehretia are 

 eaten ; the Heliotrope (Heliotr opium peruvianutri) is universally known 

 for its delicious odour. Genera : Ehretia, L. ; Tournefortia, R. Br. j 

 Heliotropium, L., &c. 



