482 D1COTYLEDONES. 



Family 23. Myrtiflorse. 



The leaves are most frequently opposite, simple, entire (rarely 

 dentate), and exstipulate. The flowers are regular and epigynous 

 (perigynous in Lythracece and a few others), ^ , polypetalous ; the 

 number of members in a whorl is generally 4 or 5 (S, P, A, or most 

 frequently A 2, G), but sometimes it becomes (e.g. Myrtles and 

 Lythracete) very large in the androecium by splitting, and in the 

 gynceceum also is often different. (When suppression takes place 

 it is principally in the corolla and petal-stamens.) In nearly all 

 instances the calyx is valvate. Gynceceum multicarpellary, 

 multilocular, with only one style (except Haloragidacefe}. In the 

 majority the ovules are situated on an axile placenta in the multi- 

 locular ovary. Endosperm is wanting in the majority. Less import- 

 ant exceptions : Rhizophoracete and Gunnera have stipules. Haloragidaceae 

 have several styles and endosperm. Rhizophora also has endosperm. 



Order 1. Lythracese. Hermaphrodite, perigynous flowers 

 which are most frequently 6-merous, viz. S 6 (often with a com- 

 " epicalyx," Fig. 519 c), one segment posterior, P6, A6 + 6 

 or 6 + and G 2-6, forming a 2-6-locular 

 ovary with many ovules in the loculi, 

 style single, and capitate stigma. The 

 gynceceum is free at the base of the 

 tubular, or bell-shaped, thin, strongly 

 veined receptacle, which bears the other 

 leaf -whorls on its edge and inner side. 

 Fruit a capsule. No endosperm. To 

 FIG. 519. Lythrum saiicaria. this order belong both herbs, shrubs and 



c the "epicalyx." 



trees. I he branches are frequently 



square, the leaves always undivided, entire, and without stipules, 

 or with several very small stipules, and often opposite. The calyx 

 is valvate. The flower is regular (except Guphea) and frequently 

 large and beautiful. The stamens are generally incurved in the 

 bud, and the petals irregularly folded. 



Lythruin (Loose-strife). The flower is diplostemonous and 

 6-merous, with a long, tubular receptacle with epicalyx-teeth 

 (Fig. 519 c). The 12 stamens are arranged in two tiers on the 

 inner side of the receptacle. The gynceceum is bi-carpellary. 

 The flowers are borne in small dichasia in the leaf-axils, and their number 

 is increased by accessory inflorescences beneath the main inflorescence. 

 The native species, L. saiicaria, is trimorphic (long-styled, mid- and short- 

 styled forms, Fig. 520). Cross-pollination is chiefly effected by humble- 



