572 



PART IV. CLASSIFICATION. 



The genus Primula has a 5-valved dehiscent capsule, and a 5-cleft calyx, 

 Primula vulgaris is the Primrose ; Primula elatior and P. veris are the Oxlip 

 and the Cowslip or Paigle ; they are remarkahle in that they are hetero- 

 styled (see p. 411). The capsule of Anagallis arvensis, the Pimpernel, de- 

 hisces transversely (pyxidium). Cyclamen europceum, the Sow-bread, has 

 an underground tuber ; the lobes of the corolla are reflexed. Lysimachia, 

 the Yellow Loosestrife, has a deeply 5-cleft calyx. Trientalis, the Chick- 

 weed Winter-green, has usually a 7-merous flower. The other British 

 genera are Hottonia (H. palustris, the Water- violet), Samolus (S. Valerandi, 

 the Brookweed), and Glaux (G. maritima, the Sea Milk-wort). 



Order 2. PLUMBAGINACE^E. Styles five : there is a single basal 

 ovule in the cavity of the ovary, pendulous on a long funicle : 

 flowers often small, in dense inflorescences with numerous bracts : 

 no trace of an external antisepalous whorl of stamens. 



In the genus Armeria the flowers are in capitula of scorpioid cymes, 

 which are surrounded by an involucre formed of the lower scarious bracts 

 with downward prolongations embracing the peduncle ; A. maritima, the 

 Thrift, occurs on sandy soils. Statice Limonium, the Sea-Lavender, with 

 racemose cymes, occurs on sandy sea-shores. Plumbago occurs in South- 

 ern Europe and in the East Indies. 



FIG. 387. A Flower of Erica: pedicel; fc calyx; c corolla; a anthers. B Fruit of 

 Pyrola rotundifolia : s pedicel ; fc calyx ; / fruit, the loculi of which alternate with the sepals ; 

 g style ; n stigma. C Flower of Foecinium afyrtiUus : /ovary (inferior); fe calyx ; c corolla. 

 Floral diagram of Erica : the stamens opposite to the petals are faintly shaded. 



Cohort VI. Ericales. Flowers 4-5-merous, actinomorphic : 

 stamens usually in two whorls and then obdiplostemonous, usually 

 hypogynous: carpels opposite to the petals: formula K(ri), C(n), 

 I An + n, 6r(n), where n = 4 or 5: ovary superior or inferior, 

 multilocular, with large recurved axile placentse : seed with en- 

 dosperm : anthers sometimes appendiculate (Fig. 277 }. 



Order 1. ERICACEAE. Anthers generally opening by two pores 

 at the top (Fig. 387 A\ often furnished with appendages : pollen 

 in tetrads : fruit a capsule, or succulent : a well-developed disc. 



