OPUNTIACEAE. 199 



ing. Androecium of 5 stamens, or of 10 stamens in 2 equal rows. Gynoe- 

 cium of 3-5 carpels. Ovary superior. Fruit a berry or a capsule. 



FAMILY 1. PASSIFLORACEAE. PASSION-FLOWER FAMILY. 



Herbs, tendril-bearing vines, or shrubby plants. Leaves with entire 

 or lobed, simple or rarely compound, blades. Corolla mostly rotate. 

 Stamens 5 : filaments usually monadelphous around the gynoecium. Fruit 

 baccate. 



1. PASSIFLORA L. Perennial vines. Leaf -blades entire, lobed, or 

 parted. Crown filamentous, single, double, or triple. Anthers versatile. 



1. P. lutea L. Twigs finely pubescent or glabrous : leaf -blades 3-15 cm. broad, 

 mostly obtuse, glabrous: cymes 1-flowered: sepals 8-12 mm. long: corolla 

 greenish-yellow, about 2 cm. broad: berries 10-15 mm. in diameter, purple. 

 Lower Susquehanna valley. Frequent, in woods, on the river shore and islands. 

 Schists. Early sum. PASSION-FLOWER. 



Order OPUNTIALES. 



Succulent typically spine-armed herbs, shrubs, or trees, nearly leafless 

 or essentially so, or leafy rigid herbs with more or less specialized hairs. 

 Flowers perfect. Hypanthium present. Calyx of 4 or 5, or of many 

 sepals. Corolla of 4 or 5, or of many petals. Androecium of usually 

 many stamens, in several series or groups, sometimes partially reduced to 

 staminodia. Gynoecium of 4, or 2-several united carpels. Ovary inferior. 

 Fruit baccate or capsular. 



FAMILY 1. OPUNTIACEAE. CACTUS FAMILY. 



Succulent plants typically spine-armed and often with cushions of 

 bristles or hairs at the base of the spines. Leaves mostly wanting or 

 obsolete. 



1. OPUNTIA [Tourn.] Mill. Plants conspicuously jointed, with separated 

 usually spine-bearing areolae. Flowers arising from the cushions of remote 

 bristles of the areolae. Style cylindric. 



1. O. Opuntia (L.) Coulter. Stems prostrate, the joints orbicular to obovate, 

 5-10 cm. long: leaves thick, 4-5 mm. long: bristle-cushions rather remote, 

 usually unarmed: bristles few, yellowish-green: spines few, when present soli- 

 tary, less than 2.5 cm. long, variegated: flowers pale-yellow, 5-6 cm. broad: 

 fruit obovoid or clavate-obovoid, 2-3 cm. long: seeds 5 mm. long, thick- 

 margined. Lower Susquehanna valley. Local, on rocks on Mountain island, 

 Peach Bottom. Schists. Spr. and early sum. PRICKLY-PEAR. INDIAN-FIG. 



Order THYMELEALES. 



Shrubs or trees, or partially herbaceous plants. Leaves opposite or 

 alternate, the blades simple, rarely mere scales, or obsolete. Flowers per- 

 fect, polygamous, or dioecious, regular or nearly so. Calyx of 5 or fewer 

 sepals. Corolla wanting (in our species). Androecium of as many 

 stamens as there are sepals or twice as many. Anthers opening by slits 



