824 MELASTOMACEAE 



Order 25. MYRTALES. 



Herbs, shrubs or trees, sometimes aquatic or amphibious. Leaves alternate 

 or opposite. Flowers regular or irregular, complete or much reduced. Hypan- 

 thium merely enclosing the ovary, or adnate to it. Perianth double, or the 

 corolla sometimes wanting. Androecium of few or many stamens : anthers open- 

 ing by slits or pores. Gynoecium 1-several-carpellary. Fruit capsular, baccate 

 or achene-like. 



Style present, simple or compound: stigma terminal. 



Anthers opening by pores. Fam. 1. MELASTOMACEAE. 



Anthers opening by longitudinal valves. 



Hypanthium merely enclosing the ovary. Fam. 2. LYTHRACEAE. 



Hypanthium adnate to the ovary or mainly so. 

 Cotyledons spirally convolute in the embryo. 



Ovary several-celled: ovules numerous, not pendulous. Fam. 3. PUNICACEAE. 

 Ovary 1-celled: ovules 2-5, pendulous. Fam. 4. TERMINALIACEAE. 



Cotyledons not spirally convolute. 



Sepals imbricated, or united and the calyx falling away as 



a cap. Fam. 5. MYRTACEAE. 



Sepals valvate. 



Leaves stipulate: sepals leathery. Fam. 6. RHIZOPHORACEAE. 



Leaves not stipulate: sepals membranous or 



herbacepus. Fam. 7. EPILOBIACEAE. 



Styles wanting: stigmas sessile. Fam. 8. GUNNERACEAE. 



FAMILY 1. MELASTOMACEAE R. Br. MEADOW-BEAUTY FAMILY. 



Herbs, shrubs or trees. Leaves opposite: blades with 3-several ribs. 

 Flowers perfect. Calyx of 3-6 sepals surmounting the hypanthium. Corolla 

 of 3-6 oblique petals. Androecium of 6-12 stamens, those opposite the petals 

 sometimes abortive. Gynoecium of 3-5 united carpels. Ovary enclosed in or 

 adnate to the hypanthium. Fruit baccate or capsular. 



Herbs: fruit a capsule. 1. RHEXIA. 



Shrubs or trees: fruit a berry. 2. TETRAZYGIA. 



1. RHEXIA L. 



Perennial herbs with rootstocks. Leaf -blades usually 3-5-ribbed. Hypanthium 

 urceolate, prolonged beyond the ovary. Sepals 4. Petals 4, deciduous. Ovary 4- 

 celled, free. Capsule included, 4-valved. MEADOW-BEAUTY. 



Anthers relatively short, oblong, not spurred at the base. 

 Corolla purple or rarely white. 



Hypanthium glandular-pubescent: upper surface of the leaf-blades gla- 

 brous. 1. R. serrulata. 

 Hypanthium glabrous: upper surface of the leaf-blades bristly. 2. R. ciliosa. 

 Corolla yellow. 3. R. lutea. 

 Anthers elongated, linear, spurred at the base. 



Neck of the mature hypanthium as long as the body or longer. 



Leaf-blades narrowly linear, the midrib only prominent and conspicuous. 4. R. Cubensis. 

 Leaf-blades not linear, the 3 nerves prominent and conspicuous. 



Stems rather sparingly pubescent with delicate hairs: leaf-blades 



nearly glabrous. 5. R. Mariana. 



Stems densely pubescent with coarse yellow hairs: leaf -blades shaggy- 

 pubescent with hairs like those on the stem 6. R. Nashii. 

 Neck of the mature hypanthium much shorter than the body. 

 Stems and branches terete or nearly so. 



Hypanthium glabrous or with a few scattered hairs. 



Leaf-blades over 2 mm. broad: hypanthium with a few scattered 



hairs. 



Leaf-blades linear to lanceolate. 7. R. lanceolata. 



Leaf-blades oval, elliptic or oblong-ovate, very thin. 8. R. delicatula. 



Leaf-blades less than 2 mm. broad: hypanthium glabrous. 9. R. filiformis. 



Hypanthium densely glandular-pubescent. 10. R. Alifanus. 



Sterns sharply angled or narrowly 4-winged. 

 Corolla over 2 cm. broad, colored. 



Sepals less than Yz as long as the hypanthium at maturity. 



Stems with pubescent internodes: hypanthium pubescent at 



maturity. 11. -R. Virginica. 



Stems with glabrous internodes: hypanthium glabrous at 



maturity. 12. R. stricta. 



Sepals fully Yi as long as the hypanthium at maturity. 13. R. aristosa. 



Corolla less than 2 cm. broad, white. 14. R. parviflora. 



