l8l. MELAsTOMATACKAE — 1 82. OENOTHERACEAE 397 



dissepiments and crowned by 4 bristle-like scales. — Species i. Mada- 

 gascar Rousseauxia DC. 



Calyx-limb entire or sinuate, ])rovided with 5 accessory teeth. Ovary 

 adhering to the calyx-tube all round. - Species 20. Madagascar. 



Veprecella Naud. 



29. Connective of the stamens appendaged behind only, not or shortly prolonged 



at the base 30 



Connective of the stamens appendaged in front or also behind, or un- 

 appendaged. Flowers 5-merous 32 



30. Stamens unequal in length. Herbs with a thickened root-stock. Leaves 



cordate, 9-nerved. — ■ Species 2. Central Africa. Cincinnobotrys Gilg 

 Stamens equal in length. Flowers 5-merous 31 



31. Calyx almost entire. Ovary crowned by 5 scales. Erect herbs with 



glandular hairs. Leaves lanceolate. Flowers in umbels. — Species i. 



East Africa Urotheca Gilg 



Calyx 5-toothed. Herbs with a very short stem and cymose flowers, or 

 climbing shrubs. — Species 15. Madagascar. Some are used as 

 ornamental plants Gravesia Naud. 



32. Stamens distinctly unequal ; connective of the longer ones lengthened at 



the base, furnished with i — 2 bosses or spurs in front, spurred or un- 

 appendaged behind. — Species 8. West Africa. Some are used as 



ornamental plants Amphiblemma Naud. 



Stamens equal or nearly so ; connective not or shortly lengthened at the 

 base, usually provided with a scale in front, rarely also with a boss 

 behind. — Species 9. Central Africa Calvoa Hook. fil. 



FAMILY 182. OENOTHERACEAE 



Leaves undivided or pinnately cleft. Flowers solitary or in spikes, heads, 

 racemes, or panicles, 2 — 6-, rarely 4-merous. Sepals valvate in bud. Petals 

 free, rarely [Ludwigia) absent. Stamens as many or twice as many as the 

 sepals. Anthers opening inwards by longitudinal slits. Ovary inferior or half- 

 inferior, completely or almost completely 2— 6-celled. Ovules inverted. 

 Style simple. Seeds exalbuminous. — Genera 10, species 40. {ON A GRA CEA E, 

 including HYDROCARYACEAE.) (Plate 116.) 



1. Ovary half-inferior, 2-celled, with one pendulous ovule in each cell. Flowers 



4-merous. Fruit top-shaped, woody, indehiscent. Floating herbs, with 

 filiform branched side-roots and broad radical leaves. — Species 2. The 

 seeds are edible and are used for preparing meal and medicaments. 



" Water Chestnut." [Tribe TRAPEAE.] Trapa L. 



Ovary inferior, 2-celled with one ascending ovule in each cell, or more 

 frequently 3 — 6-celled with numerous ovules 2 



2. Flowers 2-merous. Receptacle prolonged above the ovary in the shape 



of a stalk. Petals white or reddish. Stamens 2. Ovules and seeds 

 2. Fruit an ovoid nut with a leatherv rind, covered with hooked 



