DIV. n ANGIOSPERMAE 687 



Order 3. Primulinae 



Family 1. Primulaceae. The floral diagram (Fig. 732) shows only one whorl 

 of stamens, since these stand opposite the petals ; the outer whorl of stamens is 

 absent ; in normal Tetracyclicae it is the inner whorl that is missing. The free- 

 central placentation is characteristic. The genus Primula is widely distributed ; 

 the British species show the superior unilocular ovary with a single style, charac- 

 teristic of the family ; heterostylic. Anagallis (Fig. 733), capsule opens by a lid. 

 Cyclamen (Fig. 734). The uncooked tubers of Cyclamen and Anagallis, and the 

 glandular hairs of a number of species of Primula (P. obconica, Corthusa 

 matthioli ( w )} are poisonous. 



B. TETRACYCLICAE 



* 



1. Ovary Superior 



The Tetracyclicae have only four regularly alternating whorls in 

 the flower. They can be divided into two groups of orders according 

 to the position of the ovary. This is superior in the orders Contortae, 

 Tubiflorae, and Personatae ; in all these the ovary is composed of two 

 carpels. The orders with an inferior ovary are the Rubiinae and 

 Synandrae. In the Rubiinae the carpels are as a rule two, but 

 sometimes three or one ; in the Synandrae which are characterised by 

 the united anthers, the carpels vary from five to three, two, or 

 only one. 



These common characters having been recognised, the families 

 within the various orders may be dealt with. 



Order 4. Contortae 



Plants with decussate, usually simple leaves and actinomorphic 

 flowers, the corolla of which is often contorted in the bud. Stamens 

 epipetalous. 



Family 1. Oleaceae. This is readily recognised by the two stamens. The 

 corolla is usually tetramerous as is shown in the floral diagram of Syringa (Fig. 

 735). Besides Ligu strum, Jasminum, and Syringa, 

 Olea europaea, the Olive Tree or Olive, is the most im- 

 portant plant of the family (Fig. 736). It is a native 

 of the Mediterranean region, where it is also cultivated. 

 The flower and fruit correspond to the type for the 

 family (Fig. 737). The drupe contains a fatty oil both 

 in the succulent exocarp and in the endosperm (Fig. 

 738). Fraxinus, the Ash, differs from the type of the 

 order in having pinnate leaves ; F. excelsior has 

 apetalous, anemophilous flowers, which appear before FlG - 735. Oleaceae. 



the leaves. F. ornus, the Flowering Ash, has a Floral diagram (%n n!7 a). 

 double perianth and is entomoplulous ; it is polygamous, having hermaphrodite 

 flowers as well as female flowers with black sterile anthers ; the corolla is divided 

 to the base. It is cultivated in Sicily for the sake of the mannite it yields. 



OFFICIAL. Olea europaea yields OLEUM OLIVAE. 



