STONE-CROP FAMILY 375 



5. TILLAEASTRUM Britton. 



Small glabrous aquatic annuals. lieaves opposite, entire. Flowers perfect, 

 small, solitary, axillarv'. Sepals 4, distinct. Petals usually 4, distinct or united 

 at the base. Stamens 4. Carpels 4, distinct, several-seeded; stjdes short. 



1. T. aquaticum (L.) Britton. Stem 1-8 cm. high; leaves ILnear-oblong, 

 connate at the base, 4-6 mm. long; flowers subsessile; petals greenish, about 

 twice as long as the sepals; follicles ovoid, 8-10-seeded. Tillaea aqnalicali. In 

 mud or water: N.S. — Md. — -La.— Tex. — L. Calif. — Wash.; Eurasia. Plain — 

 Mont. 



Family 56. PARNASSIACEAE. Grass of Parnassus Family. 



Scapose perennials, mth rootstocks and basal petioled entire leaves. 

 Flowers solitary on the scape, perfect, regular. Sepals 5, imbricate. Petals 

 5, imbricate, white or nearh'' so, conspicuously veined. Stamens 5, alternate 

 with the petals and with 5 clusters of united gland-tipped staminodia. 

 Gynoecium of 3 or 4 united carpels; ovary superior or half inferior, ^\^th 3 

 or 4 parietal placentae; style obsolete; stigmas 3 or 4. Fruit a 1-celled cap- 

 sule, loculicidal at the apex. 



1. PARNASSIA. Grass of Parnassus. 



Characters of the family. 



Petals fimbriate on the sides, at least below; free portions of the staminodia very short 

 and stout; leaf-blades reniform or cordate, usually broader than long. 

 Petals obovate, 5-nerved; staminodial scales \vith 5-9 lobes; sepals elliptic. 



1. P. flmbriata. 

 Petals oblong, 3-nerved; staminodial scales with 3-5 lobes; sepals narrowly lanceolate. 



2. P. rivularis. 

 -Petals entire, not fimbriate; free portion of the staminodia long. 



Petals 5-9-veined, usually e.xceeding the sepals; capsule less than twice as long as 

 the sepals; bract some distance from the base. 

 Staminodia 7-15 in each fascicle; basal leaf-blades cordate or rounded at the 

 base. 

 Petals nearly twice as long as the sepals; hypanthium inconspicuous; stamin- 

 odia usually 9-15 in each fascicle. 3. P. palustris. 

 Petals only shghtly exceeding the sepals; hypanthium conspicuous, obconic, 

 fuUy half as long as the sepals and nearly as broad as high; staminodia 

 7-9 in each fascicle. 4. P. montanensis. 

 Staminodia 5-7 in each fascicle; basal leaf-blades acute at the base. 



5. P. parviflora. 

 Petals 3-veined, thin, scarcely equalling the sepals; capsule twice as long as the sepals; 

 bract none or near the base. 6. P. Kotzebuei. 



1. P. fimbriata Konig. Leaf -blades reniform or broadly cordate, 2-4 cm. 

 wide, thin; scape 2-3 dm. high; sepals 5-6 mm. long, elliptic or oval, obtuse, and 

 often crenulate at the apex; petals obovate, 7-8 mm. long; capsule 1 cm. long or 

 more. Springj' places in the mountains: Alta. — Colo. — -Calif. — Alaska. Mont. 

 — Subalp. Jl-S. 



2. P. rivularis G. E. Osterhout. Leaf-blades reniform or broadly cordate, 

 thin, about 7-ribbed, 1-2 cm. wide; scape slender, about 1 dm. high; sepals 

 narrowly lanceolate, acute, about 3 mm. long; petals oblong, about 6 mm. long; 

 capsule ovoid. Springy places in the mountains: n Colo. Mont. 



3. P. palustris L. Leaf-blades cordate, 1-3 cm. ^x\de; scape 1-3 dm. high; 

 sepals oblong or elhptic, 4-6 mm. long; petals oval, 8-12 mm. long; capsule 

 ovoid, about 1 cm. long. Wet places: Lab. — 'Que. — Mich. — Wyo. — Alaska; 

 Eurasia. Mont. Jl-Au. 



4. P. montanensis Fern. & Rydb. Leaf-blades ovate, with a subcordate 

 or rounded base, 1-2 cm. long, 8-18 mm. wide; scape about 2 dm. high; sepals 

 oblong to lanceolate, acute, 7-9 mm. long; petals oval to elliptic; capsule rounded- 

 ovoid, about 1 cm. long. Wet river banks: Mont. — B.C. — -Sask. Submont. — 

 Mont. Jl-Au. 



5. P. parviflora DC. Leaf -blades oval or ovate, 1-3 cm. long, 0.75-2 cm. 

 wide; scape slender, 1-3 dm. high; sepals oblong, 5-8 mm. long; petals elliptic 



