320 SYSTEMATIC BOTAKY. 



Lavandula, L. 

 Mentha, L. 

 Salvia, L. 

 Rosmarinus, L. 

 Origanum, L. 



ILLUSTRATIVE GENERA. 



Thymus, L. 

 Hyssopus, L. 

 Prunella, L. 

 Lamium, L. 

 Stachys, Benth. 



Marrubium, L. 

 Ballota, L. 

 Phlomis, L. 

 Teucrium, L. 

 Ajuga, L. 



Affinities, &c. A large and well-marked order, divided by Benth am 

 into eight tribes, according to the number, position, and direction of 

 the fertile stamens. The genera are founded on variations in the calyx and 

 corolla, &c. As regards the structure of its ovary, this Order agrees 

 exactly with Boraginacese, from which, however, almost all its other 



characters distinguish it. The ordinary structure is S 5 | P5 A~4 G~2, as 

 for all Orders with didynamous stamens. Among the didynamous un- 

 symmetrical monopetalous Orders, no other group approaches this struc- 

 ture but Verbenaceae, which are distinguished by the greater degree of co- 

 herence of the carpels and the terminal style, as the Ehretiaceae are from 

 Boraginaceae ; but the separation of these Orders is sometimes difficult. 

 Disregarding the ovary, the character of the corolla and stamens connects 

 Labiate with Scrophulariaceae and its allies, especially when they have 

 opposite leaves and square stems. The morphology of the corolla and 

 stamens is very interesting in this Order, as it is in the Scrophulariacese ; 

 the didynamous structure arises from the want of the posterior stamen, 

 and in the diandrous genera it is the anterior pair that remains. Payer 

 says there are originally five stamens in Labiates, two anterior first deve- 

 loped, then two lateral, while the fifth or posterior is the last to appear, 

 and indeed is often suppressed or present in the shape of a gland. The 

 anterior first-born stamens are the longest and their anthers open first. 

 The foliage of the majority of plants in this Order is studded with micro- 

 scopic glandular hairs, containing the essential oils to which they owe 

 their remarkable fragrance. Various species of Salvia have hairs upon 

 the testa of the seed, containing a spiral fibre, somewhat as in Polemo- 

 niacese. 



Distribution. A very large Order, the species of which are principally 

 natives of temperate climates ; but the more fragrant kinds occur mos't 

 abundantly in the warm temperate and drier regions. 



Qualities and Uses. The most striking qualities of this Order depend 

 upon the presence of aromatic or fragrant essential oils, which render some 

 of them valuable stimulants and antispasmodics, others favourite flavour- 

 ing herbs for culinary purposes, others important ingredients in perfumes, 

 &c. Some are also regarded as tonics. The fleshy subterraneous rhizomes 

 of Stachys palustris are sometimes cultivated as a table vegetable j and 

 the tubers of an Odmum are said to be eaten in Madagascar. Of the car- 

 minative arovnatics, the Mints, Spearmint (Mentha viridis), Peppermint 

 (M. Piperita), Penny-royal (M. Pulegiuni} are among the best known. 

 Other species of Mentha have similar properties ; Hedeoma pulef/ioides, 

 the Penny-royal of the United States ; Lavender, Lavandula vera ; to- 

 gether with the inferior French Lavender, L. Sjrica, the oil of which, 

 however, is chiefly used in the arts (oil of Spike), and others : many allied 



