GROUP V. ANGIOSPERM^E ; DICOTYLEDONES. 



553 



on the surface of the water ; in the axils of these leaves the flowers are 

 borne singly : their formula is K, (74, A4, <?<?), and they are perigynous : 

 the fruit is indehiscent, and the sepals remain adherent to it in the form 

 of four horns : it contains two seeds. 



Order 2. LYTHRAOE^E. Flowers perigynous, with usually both 

 whorls of stamens : formula Kn, On, | ^4n + n, G (2 - ) , where n = 3 

 16 : ovary free in the hollow receptacle : an epicalyx formed by 

 connate stipules is often present : seed without endosperm. 



Lythrum tialicaria, the Loosestrife, occurs in bogs and ditches : flower 

 usually pentamerous or hexamerous : the stamens of the two whorls are 

 unequal in length, and the length of the style also varies ; three forms of 

 flowers are thus produced (trimorphism ; see p. 412). The other British 

 genus is Peplis ; P. Portula is the Water-Purslane ; it has usually hexa- 

 merous flowers and an indehiscent fruit: gynaeceum dimerous in both 

 genera. 



FIG. 365. Longitudinal section of 

 the flower of Calorhamnus ; /ovary; 

 s calyx; p corolla; st antipetalous 

 bundle of stamens; g style. (After 

 Sachs). 



FIG. 366. Flower-bud of Jamboa 

 Caryophyllus, the Clove, in longitudi- 

 nal section ; / the inferior ovary, with 

 the oil-glands (<!>) ; sk the ovules ; k 

 calyx ; c corolla ; st stamens ; a an- 

 thers ; g style (enlarged) . 



Order 3. MYRTACEJE. Flowers 4- or 5-merous, epigynous : sta- 

 mens often very numerous, free, or connate in usually antipetalous 

 bundles (Fig. 365) ; sometimes few and obdiplostemonous : ovary 

 1 oo-locular ; seeds 1-x in each loculus, without endosperm: 

 placentation and fruit various : leaves usually opposite, dotted 

 with oil-glands. Shrubs or trees. 



Myrtus communis is the Myrtle of Southern Europe ; the genus Eugenia 

 includes a number of ornamental shrubs, among which is E. (Jambosa) 

 Ceiryopkytttit, the buds and flowers of which yield the spice known as 

 cloves (Fig. 366). Eucalyptus Globulus, from Australia, is much planted 



