VERBENACEAE 243 



697. Aegiphila Jacq. 



2216. A. elata Sw., and 2217. A. mollis Jacq. Darwin describes these 

 species as dimorphous (' Different Forms of Flowers '). 



2218. A obducta. Darwin (J. Linn. Soc. Bot., London, vi, 1862) describes 

 this species as dioecious. 



LXXXIL ORDER LAB I ATA E JUSS. 



Literature. Sprengel, * Entd. Geh./ pp. 303-4 ; Herm. Miiller, ' Fertilisation/ 

 pp. 469-503; Knuth, *B1. u. Insekt. a. d. nordfr. Ins., p. 116, 'Grundriss d. 

 Bliitenbiol.,' p. 83 ; Briquet, ' Labiatae,' in Engler u. Prantl's ' D. nat. Pflanzenfam.,' 

 IV, 3 a, pp. 200, 201, 202, 225-72, 273-320, 321-80. 



The inflorescences are usually very conspicuous, and attract numerous insects, 

 which, as Hermann Miiller points out, belong to very varied groups. The kind of 

 visitor depends on the length of the corolla-tube, at the bottom of which the nectar 

 secreted at the base of the ovary is concealed. The short-tubed flowers of Mentha 

 and Lycopus are mostly visited by flies ; in the case of Thymus and Origanum not 

 only these but also bees in increasingly large numbers are to be found ; in Betonica 

 flies and bees play an almost equally important part; Stachys palustris Z. and 

 S. sylvatica Z. are visited by bees in a decided majority ; and, finally, Lavandula, 

 Salvia, Lamium, Galeopsis, Ballota, Teucrium, and Ajuga are pollinated almost 

 exclusively by bees, the only exceptions being in the case of some Lepidoptera and 

 Diptera with the most elongated mouth-parts. The last-named group belong therefore 

 to flower-class H, the first-named to C. Scutellaria, and also Teucrium pyrenaicum 

 Z., possess a Lepidopterid door as well as one for humble-bees, belonging therefore to 

 Hh and Lb. The lower lip selves as a convenient alighting-platform, while the 

 upper one holds the anthers and stigma in certain relative positions, and at the same 

 time forms a protective roof for the stamens. If this upper lip should be absent, it 

 is frequently replaced by bracts projecting beyond the flower. The corolla-tube is 

 often so much bent that its curve corresponds to that of a humble-bee's proboscis. 

 In many cases automatic self-pollination is completely or partially prevented by 

 dichogamy; in homogamous flowers it is entirely or temporarily hindered by the 

 relative positions of stamens and pistil. 



Briquet distinguishes two oecological flower types. In the first, the butterfly 

 type, the anterior part of the corolla is produced in front, and the stamens and style 

 are situated on the lower lip. The secretion of nectar sometimes takes place in the 

 upper-side of the flower, and pollen is then scattered on the legs and under-sides 

 of insects. There are four varieties of this type : (i) The Ocimoideae are 

 constructed entirely according to the described plan. They are to a large extent 

 protandrous bee and humble-bee flowers. (2) The flowers are resupinate by torsion 

 of the pedicel, so that the positions of the upper lip and the reproductive organs 

 are reversed (e.g. Lophanthus chinensis Benth.). (3) Resupination results from 

 torsion of the corolla-tube (Ajuga orientalis Z., Teucrium spinosum Z., T. resu- 

 pinatum Des/., and all species of Satureia belonging to the group Cyclotrichium). 



R 2 



