KEY TO THE HYDRANGEAS 195 



cultivated as a tub plant North and as a hardy plant South that it de- 

 serves a paragraph of description. It has been in cultivation for so many 

 centuries by those most successful horticulturists of eastern Asia that 

 there are hundreds of named varieties. These can be separated into 

 three well-marked groups and for such a handbook as this no more, of 

 practical value, can be included : — 



1. The Jap6nica group with broad flat clusters of mixed sterile and 

 fertile flowers (299). 



2. The Hort^nsia group with nearly globular clusters of almost all 

 sterile flowers (300). 



3. The Stell^ta group with flowers having many narrow divisions 

 (sepals) . [Twig cuttings ; layers ; suckers ; divisions. ] 



KEY TO THE HYDRANGEAS 



* Flowers abundant in large pyramidal clusters. (A.) 



A. Leaves not lobed, large, 2-5 inches long, serrate ; flower-clusters 



6-12 inches long, flowers whitish, the large, sterile ones changing 



to purplish (Aug., Sept.) ; capsule with the calyx at about the 



middle. (B.) 



B. About half of the flowers sterile, July-Sept. ; shrub or tree to 



30 feet. Panicled Hydrangea — Hydrangea paniculata. 

 B. Three fourths of the flowers sterile and larger. Abundant- 

 flowered Hydrangea — Hydrangea paniculata floribunda. 

 B. Nearly all the flowers sterile in extra large clusters. Large- 

 flowered Hydrangea (298) — Hydrangea paniculata grandi- 

 flora. 

 A. Leaves 3-7-lobed, large, 4-8 inches long ; flowers pinkish, June, 

 July ; shrub with spreading branches to 6 feet. Oak-leaved 

 Hydrangea (301) — Hydrangea quercifolia. 



* Flowers in broad flat or globular clusters. (C.) 



C. Styles of the pistil usually 2 ; capsule with the calyx at the tip. (D. ) 



D. Flower-clusters wrapped, before expanding, with 6-8 large 



deciduous bracts ; low shrub to 5 feet. Hydrangea involucrata. 



D. No such bracts ; erect shrubs 4-10 feet ; leaves 3-6 inches long 



on long stalks. (E.) 



E. Leaves nearly smooth on both sides, ovate to cordate. (F.) 



F. Very few enlarged sterile flowers. Wild Hydrangea 



(302) — Hydrangea arbor^scens. 

 F. About all the flowers sterile. Hills of Snow — Hy- 

 drangea arbor^scens st^rilis. 

 F. Leaves especially broad and heart-shaped. Heart-leaved 



