192 CISTACEAE. 



slightly clasping: cymes few-flowered: sepals oblong to oblong-obovate, 4-5.5 

 mm. long: petals bright-yellow, 7-10 mm. long: capsules globose-ovoid, 4-5 

 mm. long, obtuse. S. Islands and sandy shore of the Susquehanna. Schists. 



6. H. prolificum L. Plants shrubby, 3-12 dm. tall, the branches narrowly 2- 

 winged: leaf -blades narrowly oblong or rarely lanceolate, 2-8 cm. long, short- 

 petioled: cymes few-flowered, short-peduncled, in cylindric panicles: sepals 

 mostly obovate, 4-6 mm. long: petals deep-yellow, 8-10 mm. long: capsules 

 conic or narrowly ovoid, 8-10 mm. long, acute. Susquehanna valley. Fre- 

 quent, on shores and islands. SHRUBBY ST. JOHN 'S-WORT. 



7. H. Ascyron L. Plants mostly 1-2 m. tall: leaf -blades ovate-lanceolate to 

 oblong-lanceolate, or narrowly ovate, 3-8 cm. long, obtuse or acutish, clasping: 

 cymes few-flowered: sepals ovate, 7-11 mm. long: petals bright-yellow, 2-2.5 

 cm. long: capsules conic, 2-3 cm. long. M. S. Islands and shore of the 

 Susquehanna, and along the Little Conestoga. Limestones, schists. 



3. SAROTHRA L. Partially succulent annual herbs. Sepals 5, equal or 

 nearly so. Stamens grouped. Styles relatively long. Capsule exserted. 



1. S. gentianoides L. Stems 1-5 dm. tall: leaves scale-like, appressed, often 

 subulate or those on the lower part of the stem sometimes linear or narrowly 

 oblong: sepals linear or linear-lanceolate, 2-3 mm. long: corolla yellow, 4-8 

 mm. broad : stamens 5-10 : capsules conic, 4-5 mm. long. Common, in sandy 

 and gravelly soil. Sum. PINEWEED. ORANGE-GRASS. 



4. TRIADENUM Baf. Herbs, resembling species of Hypericum. Sepals 

 5, equal. Stamens mostly 9, grouped in 3 's, the filaments of each group well 

 united. Styles relatively long. Capsule exserted. 



1. T. virginicum (L.) Eaf. Stems 2-6 dm. tall: leaf -blades oblong, elliptic, 

 or ovate, 2-1Q cm. long, obtuse, clasping: sepals lanceolate to oblong, 5-6 mm. 

 long, acute: petals obovate to oblanceolate or nearly oblong, 8-10 mm. long, 

 acute, delicately nerved : capsules oblong, 8-10 mm. long. N. S. Eare, in 

 swamps. Sandstones and shales, schists. Sum. MARSH ST. JOHN 'S-WORT. 



FAMILY 2. CISTACEAE. ROCK-ROSE FAMILY. 



Shrubs or partially woody plants. Leaves alternate or opposite: 

 blades simple. Flowers generally perfect. Calyx of 3-5 persistent sepals. 

 Corolla of 5 or 3 often fugaceous petals, or wanting. Androecium of 6 or 

 more stamens. Gynoecium of usually 3 united carpels. Fruit a capsule. 



Petals 5, yellow, fugaceous, or wanting : stigmas not fimbriate. 1. CKOCANTHEMUM. 

 Petals 3, not yellow, marcescent-persistent : stigmas fimbriate. 2. LECHEA. 



1. CROCAJNTHEMUM Spach. Erect plants. Leaf -blades linear or wider. 

 Flowers complete and showy, and with many stamens in the early part of the 

 season, inconspicuous and with few stamens later or sometimes all conspicu- 

 ously petaliferous. Ovules pendulous. Capsules of the petaliferous flowers 

 larger than those of the apetalous ones. EOCK-ROSE. 



1. C. canadense (L.) Britton. Stems 1-6 dm. tall: leaf -blades oblong, linear- 

 oblong, or oblanceolate, nearly sessile, 1.2-3 cm. long, rough and dark-green 

 above, paler and canescent beneath: petaliferous flowers with 30 stamens and 

 30-60 ovules, their corollas 1.8-3 cm. wide, their capsules ovoid or obovoid and 

 6-8 mm. long: apetalous flowers appearing later, axillary, nearly sessile, with 

 4 stamens and 6-20 ovules, their capsules about 4 mm. in diameter: seeds 

 papillose. Common, on dry banks and in stony soil. Spr. and sum. 

 FROST-WEED. 



