HEATH FAMILY 



Leaves. — Alternate, usually clustered at the ends of the branches, 

 persistent, elliptical, oblong, four to ten inches long, wedge-shaped 

 or rounded at base, entire, thickened slightly, revolute margin, 

 acute apex. They come out of the bud revolute, pale green, cov- 

 ered with thick pale tomentum. When full grown are smooth, 

 thick, leathery, dark green and shining above, pale beneath ; mid- 

 rib broad, pale, depressed above, prominent beneath ; veinlets ob- 

 scure. Petioles stout, short, terete. 



Flowers. — June, after the shoots of the year from the buds below 

 the flower-buds are well grown. Borne in umbellate clusters four 

 or five inches in diameter, perfect, pale rose, or white. Pedicels 

 viscid ; bracts caducous. 



Calyx. — Five-lobed ; lobes rounded, imbricate in bud. 



Corolla. — Campanulate, gibbous on the posterior side, hairy in 

 the throat, pale rose, purplish, or white, five-lobed ; lobes rounded, 

 veined ; upper lobe marked with yellow greenish spots. 



Sta7nens. — Eight to twelve, white, inserted on a disk ; filaments, 

 unequal, declined, bearded ; anthers attached on the back, two- 

 celled ; each cell opening by a terminal pore. 



Pistil. — Ovary superior, five-celled, hairy ; style long, white, de- 

 clined ; stigma red, five-lobed ; ovules many in each -cell. 



Fruit. — Capsule, surrounded at base by the persistent calyx and 

 crowned with the style. 



The Rhododendron becomes a tree in the south only ; on 

 the mountains of Pennsylvania, New York, and Virginia it 

 remains a shrub, but one of the most attractive shrubs in our 

 flora. Both leaf and flower are matured in midsummer and 

 they are so large and crown the summit of the stem so per- 

 fectly that they cannot escape observation. 



The Rhododendron, the. Kalmia, the Holly, and the Holly- 

 leaved Mahernia make up our northern list of broad-leaved 

 evergreens. All other broad-leaved trees of our flora have 

 become deciduous. Here and there individual oaks retain 

 their leaves all winter ; so do many young beeches. These 

 persistent leaves are brown and withered it is true, but they 

 speak of a time when the trees were evergreen. The Oak 

 family still retains an evergreen species, and in South 

 America the forests of Patagonia wave green and dark with 

 an evergreen beech. 



The Rhododendron flourished in the arctic regions in 

 tertiary times, and traces of several species are found in the 

 miocene rocks of Europe. 



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