BOTANY. 157 



the tube of the calyx , aestivation twisted. Stamens usually four or eight 

 (rarely one or two), epigynous ; filaments distinct ; pollen triangular, 

 usually cohering by threads. Ovary two- to four-celled, adherent, usually 

 with an epigynous disk ; style filiform ; stigma capitate or four-lobed ; 

 ovules indefinite, rarely definite, anatropal. Fruit succulent or capsular, 

 dehiscent or indehiscent, one,- two,- to four-celled. Seeds usually cc, 

 exalbuminous ; embryo straight, with a long slender radicle pointing to the 

 hilum, and short cotyledons. Herbs or shrubs, with alternate or opposite, 

 simple, not dotted leaves, and with the parts of the flower usually 

 tetranerous. They inhabit chiefly temperate regions, and are found 

 abundantly in Europe, Asia, and America, and sparingly in Africa. 



Tribe 1. Jussieuece. Calyx divided immediately above the ovary. 

 Number of stamens equal to, or double that of the petals. Fruit capsular, 

 with septicidal dehiscence, many seeded. Cotyledons straight. Examples : 

 *Jussieua, *Ludwigia. 



Tribe 2. OnagrecB. Calyx with the tube more or less elongated. 

 Number of stamens double that of petals. Fruit capsular with loculicidal 

 dehiscence, many seeded. Cotyledons straight. Examples : *Oenothera, 

 *Gayophytum, *Epilobium. 



Tribe 3. Gaurece. Calyx with the tube elongated. Number of stamens 

 double that of petals. Fruit indehiscent, nucumentaceous, one- to four- 

 seeded. Cotyledons twisted. Examples : *Gaura, *Stenosiphon. 



Tribe 4. FuchsiecB. Calyx with the tube elongated. Number of 

 stamens double that of petals. Fruit fleshy. Cotyledons sti'aight. 

 Example : Fuchsia. 



Tribe 5. Lopeziece. Tube of calyx elongated. Petals four or more. 

 Stamens two or one. Fruit capsular, many seeded, with loculicidal 

 dehiscence. Example : Lopezia. 



Tribe 6. CircaecB. Calyx divided into two segments immediately above 

 the ovary : petals two ; stamens two. Fruit indehiscent, two-locular, two- 

 seeded. Examples : Circaea. 



Of the above order there are about 30 genera and 450 species. North 

 America has 12 genera and 117 species. Among the more prominent 

 species is Oenothera biennis, the Evening Primrose. 



Oenothera biennis, Evening Primrose, United States {pi. 69, fig. 6) ; a, 

 a flowering branch ; b, calyx ; c, stamen ; d, vertical section of calyx tube ; 

 e, burst capsule ; f, cross-section of do. ; g, seed. 



Epilobium angustifolium, Willow-herb (Europe) {pi. 69, fig. 7) ; «, a 

 flow^er branch ; b, calyx with style and a stamen ; c, burst capsule ; d, a seed. 



Order 145. MyRTACEiE, the Myrtle Family. Calyx four-, five-, six- to 

 eight-cleft, the limb sometimes cohering at the apex, and falling off' like a 

 lid ; sestiration valvate. Petals attached to the calyx, alternating with its 

 segments, and equal to them in number, with a quincuncial jcstivation, 

 rarely 0. Stamens inserted with the petals, twice as many as the petals, or 

 «o ; filaments distinct, or united in one or more parcels, curved inwards in 

 the bud ; anthers ovate, dithecal, with longitudinal dehiscence. Ovary 

 adherent to the tube of the calyx, one- to six-celled ; style and stigma 



157 



