570 PART IV. CLASSIFICATION. 



arvensis (Common Bugloss), Cynoglossum officinale (Hound's-tongue), and 

 Borago ojficinalis, the Borage, are common. Anchusa officinalis, the Alkanet ; 

 Mertensia maritima, the smooth Gromwell or Sea-Bugloss ; and Pulmonaria 

 anyustifolia, the Lung- wort, are rare in Britain. 



Cohort IV. Gentianales. Flowers regular, but with oli- 

 gomery in the gynseceum : perianth and androecium usually 4- or 

 5-merous : corolla with frequently contorted aestivation (to the 

 right) : stamens inserted on the tube of the corolla : carpels two : 

 leaves commonly decussate and exstipulate : formula J5T(5) [C(5) 

 Ao] G. 



Order 1. GTENTIANACE.E. Carpels are perfectly connate, forming 

 a uni- or incompletely bi-locular ovary : ovules parietal, numerous, 

 anatropous : seed with endosperm. Usually herbs without milky 

 latex : leaves almost entire. 



Sub-order 1. GENTIANEJE. Leaves decussate : corolla with contorted 

 aestivation. 



Gentiana the Gentian, has a bilobed stigma ; it occurs in mountainous 

 districts. Erythrsea has a capitate stigma ; E. Centaurium, the common 

 Centaury, is common in pastures (Fig. 384). Species of Cicendia and Chlora 

 also occur in Britain. 



Sub-order 2. MENYANTHE^E. Leaves spiral: corolla with valvate sesti- 

 vation. 



Menyanthes trtfoliata, Buck-bean or Bog-bean, with ternate leaves, is 

 common in marshes : Vittarsia nymphceoides (or Limnanthemum peltatum) is 

 found in ponds and rivers. 



Order 2. OLEACE.E. Calyx and corolla usually 4-merous, some- 

 times wanting ; stamens and carpels two, alternate : ovary bilo- 

 cular : ovules 2 in each loculus : fruit a capsule, a berry, a drupe, 



FIG. 385. A Flower of Fraxinus Omus (enlarged): 7: calyx; c corolla; st stamens; 

 /ovary; n stigma. B 9-flower of Fraxinus excelsior, the common Ash; an anthers; 

 / ovary ; n stigma (enlarged). Floral diagram of the Oleacese. 



