352 THE HIGHER DICOTYLEDONS. 



356. The Dead-nettle Family (Labiatae) is one of the 

 most easily recognised, all the Labiates having square stems, 

 simple decussate leaves without stipules, corolla generally 

 two-lipped with no clear indication of the separate petals, 

 stamens generally in two pairs owing to suppression of the 

 upper one (sometimes only two stamens present), ovary of 

 2 carpels, but with four one- seeded chambers. 



By the ovary and fruit (four akenes) Labiates are dis- 

 tinguished from those plants of the Foxglove Family which 

 have square stems, decussate leaves, and bilabiate flowers 

 with two pairs of stamens. By the decussate leaves, bilabiate 

 corolla, and the presence of four stamens Labiates are dis- 

 tinguished from the Borage Family, in which the ovary and 

 fruit are similar in structure. 



357. Flower Mechanisms in Labiatae. In most 

 Labiates the flower is protandrous, and in many cases the 

 stamens move outwards or downwards (well seen in Wood 

 Sage) after the anthers have opened, when the style moves 

 into their place and the stigmas spread apart to receive 

 pollen. When the flower is homogamous, the style projects 

 below the anthers so as to be touched first by the visiting 

 insect. In the short-tubed flowers of Mint, G-ipsywort, 

 Thyme, and Marjoram, with more or less regular corolla and 

 spreading stamens, all sorts of insects crawl over the flowers 

 and touch the anthers and stigmas with any part of their 

 bodies. 



Most British Labiates, however, are definitely "bee- 

 flowers " and have a conspicuous lower corolla-lip to attract 

 insects and to act as a landing-place, and usually an arched 

 upper-lip to shelter the stamens and style, which are gener- 

 ally placed so as to touch the bee's back as it enters the 

 flower. 



In Sage (Salvia) the two stamens (the other pair is repre- 

 sented by small staminodes) have a peculiar structure ; they 

 are ~J~- sna P e< l> the filament being short and jointed to the 

 long connective. In the lower types of Salvia each end of 

 the connective bears a half -anther, but in the higher types 

 (e.g. G-arden Sage, which should be examined) the lower end 

 of the connective is barren and flattened and the outer 

 (upper) part of the connective is longer than the inner (lower) 



