THE DICOTYLEDOXES 1929 



though in Mentha it is nearly regular. It is gamopetalous, hypogynous, 

 tubular and four-lobed, the two posterior petals being united to form the 

 upper lip. 



The androecium consists of four epipetalous and didynamous stamens, 

 the fifth being suppressed. The fifth posterior stamen is sometimes [Salvia) 

 represented by a staminode, while in Lycopus and Salvia the two upper 

 stamens are also suppressed. In Coleiis the stamens are monadelphous. 



The gynoecium is bicarpellary and syncarpous, but at a very early 

 stage in the development of the ovary a constriction is produced which 

 divides the ovary into four segments each containing a single ovule. The 

 style is bifid and gynobasic except in the Ajugoideae and Prostanthera. The 

 placentation is axile or basal. 



The fruit is a carcerulus consisting of four nutlets which are either free 

 or united in pairs. 



The seed is usually non-endospermic and the embryo is usually 

 straight. 



The family is a large one represented by nearly 200 genera containing 

 over 3,000 species generally distributed in warm and temperate regions, 

 and is particularly well represented in the Mediterranean region. Some 

 small groups are restricted to Australia and Tasmania, India, China, 

 Malaya and Central America. Many occur under semi-desert conditions 

 and are sometimes characterized by small needle-shaped leaves in which 

 the stomata are restricted to hair-covered grooves on the lower surface. 



The family is of considerable economic importance on account of the 

 volatile oils, obtained from the leaves, many of which are used in perfumery. 

 Among the more important of these are Lavender, Rosemary, Peppermint 

 and Patchouli. Several genera, as already mentioned, are used as culinary 

 herbs, while Stachys sieboldii produces edible tubers known as Chinese 

 Artichokes. 



The family is subdivided by Briquet in the following somewhat elaborate 

 way. 



I. Ajugoideae 



Style not gynobasic; fruit consisting of nutlets with lateral placentation. 

 Seed non-endospermic. 



1. Ajugeae. Corolla various, upper lobe if present rarely concave. 



Stamens four to two, anthers bilocular. Nutlets more or less 

 wrinkled. Teiicrium, Ajuga. 



2. Rosmarineae. Corolla strongly two-lobed with upper lobe concave 



and arched. Stamens two, anthers unilocular. Nutlets smooth. 

 Rosmarinus. 



II. Prostantheroideae 



Style not gynobasic; fruit consisting of nutlets with lateral placentation, 

 seed endospermic. Only genus Prostanthera. 



III. Prasioideae 



Style gynobasic; fruit consisting of nutlets with basal placentation, 



