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 Jap(5nica 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 StellJita 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 panicuUta. 

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

 flowered Hydrangea — Hydrangea paniculJita floribiinda. 

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

 flowered Hydrangea (298) — Hydrangea paniculJita grandi- 

 flbra. 

 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 quercifblia. 



* 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 involucrita. 



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.) 



P. Very few enlarged sterUe flowers. Wild Hydrangea 



(.302) — Hydrangea arborfiscens. 

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

 drangea arbor&cens st^rilis. 

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



