Trees of the Northern Unitep States 147 



Raceme. An elongated inflorescence with each flower on a 



peduncle. 

 Rachis. The axis of a compound leaf, spike, or raceme. 

 Receptacle. The end of the flower stalk bearing the floral 



organs. 

 Reflexed. Bent backward abruptly. 



Regular. Having the parts of each set alike in size and shape. 

 Reniform. Kidney-shaped. 

 Repand. With a more or less wavy margin. 

 Refuse. With a shallow notch at the end. 

 Revolute. Rolled backward. 

 Rotate. With a flat round corolla ; wheel-shaped. 



Sagittate. Shaped like an arrow head. 



Samara. A simple indehiscent winged fruit. 



Scabrous. Rough. 



Scale. A highly modified dry leaf as in the winter bud of 



most plants; also a dry, flat, more or less membranous 



outgrowth from a leaf or stem. 

 Scurfy. Covered with scurf, minute membranous scales, as 



in Chenopodium. 

 Scarious. Thin, dry, and translucent, not green. 

 Seed. The matured and modified ovule with a dormant 



embryo. 

 Self-pruning. The process by which living buds or twigs are 



naturally separated from the plant. 

 Self-pruning scar. A scar produced where a twig or bud has 



1)een self-pruned. 

 Sepal. One of the leaves of a calyx. 

 Septicidal. A capsule which splits longitudinally through its 



partitions thus dividing it into its component carpels. 

 Serrate. With teeth projecting forward. 

 Sessile. Without a stalk. 

 Sinuate. With strongly wavy margins. 

 Sinus. The space between two lobes. 

 Spermary. The male reproductive organ. 

 Spermatozoid or sperm. The male gamete. 

 Spike. An elongated inflorescence with sessile or nearly 



sessile flowers. 



