HYDEANGEACEAE 505 



1. HYDRANGEA L. 



Shrubs or trees. Leaves opposite, without stipules: blades entire, toothed, or 

 lobed. Flowers perfect, except a few conspicuous ones around the edge of the corymb 

 or thyrse. Sepals united into a truncate or 4-5-toothed border, or in sterile flowers 

 of 4-5 spreading petal-like lobes. Petals 4-5, valvate. Stamens 8-10, inserted at the 

 base of an epigynous disk: filaments filiform. Ovary inferior, completely or partially 

 2-4-celled: styles 2-4, distinct or slightly united at the base. Ovules numerous, borne 

 on axile placentae. Capsule 2-4-celled, membranous, opening at the top between the 

 styles. Seeds numerous, minute. Testa membranous, reticulated. The plants flower 

 during the spring and summer. 



Leaf-blades merely toothed : inflorescence corymbose. 



Leaf-blades glabrous or inconspicuously pubescent beneath: hypanthium 

 T f^u?*^'^ wider than high. 1. H. arborescens. 



LeaJ-blades conspicuously and copiously pubescent beneath: hypanthium 

 mostly higher than wide. 

 Leaf-blades membranous, light gray beneath. 2. H. cinerea. 



J . Leaf-blades leathery, bright white beneath. 3. H. radiata. 



i^eai-blades deeply lobed: inflorescence thyrsoid. 4. H. quercifolia. 



1. Hydrangea arbor6scens L. A branching, sometimes straggling shrub 1-3 m. 

 tall. Leaf-blades ovate, oval or elliptic, 0.5-2 dm. long, short-acuminate, serrate, 

 acute, rounded or cordate at the base, glabrous or sometimes minutely pubescent 

 beneath; petioles shorter than the blades: corymbs 5-20 cm. broad, usually with few 

 sterile ray-flowers or these wanting, commonly pubescent: hypanthium campanulate, 

 1-1.5 mm. broad: sepals minute, triangular: petals deciduous, concave, ovate, about 

 1 mm. long: stamens conspicuously exserted: stigmas reddish: capsules 2 mm. broad, 

 8-ribbed, broader than high, each tipped with the 2 spreading styles. 



In woods or along streams, New York to Iowa, Florida and Louisiana. 



_ 2. Hydrangea cinerea Small. A spreading shrub, 1-2 m. tall, with deep green 

 foliage. Leaf-blades thinnish, oval, elliptic, narrowly ovate or orbicular-ovate, 6-15 

 cm. long, acuminate, serrate, obtuse, rounded or cordate at the base, bright green 

 above, gray-tomentose and not reticulated beneath; petioles somewhat more than one- 

 half as long as the blades or shorter: corymbs 5-15 cm. broad, rather round-topped: 

 sterile ray-flowers commonly present: hypanthium campanulate, ribbed: sepals tri- 

 angular, acute: petals 5, ovate, boat-shaped, 1.5 mm. long, hooded at the apex: 

 stamens conspicuously exserted: capsules urn-shaped, about 2 mm. in diameter, usually 

 higher than broad, strongly ribbed, each tipped with the 2-3 spreading styles. 



On the slopes of the Alleghenies, North Carolina, Tennessee, Georgia and Alabama. 



3. Hydrangea radikta Walt. A branching shrub, 1-2.5 m. tall. Leaf-blades 

 leathery, ovate, varying to oval or ovate-lanceolate, 6-12 cm. long, acuminate, serrate 

 or crenate-serrate, acute, rounded or subcordate at the base, bright green and glabrous 

 above, densely silvery white-tomentose and reticulated beneath; petioles about * as 

 long as the blades or shorter: corymb round-topped, 4-12 cm. broad: sterile flowers 

 always present: hypanthium urn-shaped, ribbed: sepals triangular or usually some- 

 what acuminate: petals 5, ovate, concave, nearly 1 mm. long, apiculate: stamens much 

 exserted: capsules urn-shaped, 2 mm. broad, strongly ribbed, shorter than their 

 pedicels, each tipped with the 2 spreading swollen styles. 



On rocky slopes, North and South Carolina. 



4. Hydrangea quercifolia Bartr. A stout shrub, 1-2 m. tall, with densely 

 tomentose twigs and branches. Leaf-blades oval or suborbicular in outline, usually 

 5-lobed, 6-20 cm. long, tomentose beneath, the lobes serrate and often slightly lobed; 

 petioles i—k as long as the blades: panicles 1-2 dm. long: sterile flowers numerous, 

 white, turning purple: hypanthium urn-shaped, longer than the pedicel: sepals ovate, 

 about J as long as the hypanthium: petals 5, oblong, 1.5 mm. long, slightly concave: 

 stamens conspicuously exserted: capsules urn-shaped, 2.5 mm. in diameter, ribbed, 

 each tipped with the spreading much enlarged styles. 



On river banks, middle Georgia to Florida and Mississippi. Grat-beabd. Old Man's- 



BEABD. 



