158 WOODY PLANTS 



HEDERA L. (Araliaceae) 



Woody evergreen climbers or trailers, with aerial roots as 

 climbing organs. Stems moderate, terete; pith moderate, spongy. 

 Buds small, conical, solitary, sessile, naked or with about 2 

 fleshy scales. Leaves alternate, palmately lobed and cordate, or 

 lanceolate, ovate, or deltoid on older pendent shoots. Leaf-scars 

 U-shaped, somewhat raised; bundle-traces 5 or 7; stipule scars 

 lacking. 



1. H. helix L. English Ivy . Leaves 3-5-lobed. Introduced from 

 Europe, cultivated and becoming naturalized (Fig. 230). 



CORNUS L. (Cornaceae) 



Deciduous shrubs or small trees. Twigs slender, round ;pith 

 moderate, round, continuous or porous. Buds usually solitary, 

 stalked or sessile, typically oblong. Leaf-scars usually opposite, 

 crescent-shaped, commonly raised on petiole bases; bundle-traces 

 3; stipule-scars lacking, but the leaf-scars often meet or are 

 joined by transverse lines which may resemble stipule-scars on 

 cursory examination. 



a. Low subshrub, 9-22 cm. high l.C. canadensis 



a. Taller shrubs or trees 



b. Leaf- scars opposite 



c. Leaf-scars during the first win- 

 ter on the ends of petiole-bases 

 covering the leaf-buds; flower- 

 buds biscuit-shaped 2.C. florida 



c. Leaf-buds not concealed by , 



petiole-bases •^"'" \09f 



d. Cyme-vestiges corymbose 



e. Pith of 1-2-year old 

 branchlets white 



f. Branchlets red or brown, 



some of them prostrate 



and rooting at the tips 



(stoloniferous) 3. C. stolonifera 



f. Branchlets greenish, 



becoming pink in 



winter 4.C. rugosa 



