GLOSSARY. 315 



Seed. The body containing the embryo plant: the ripened ovule. 

 Seedling. In nursery practice a young plant grown from seed and 



not having been transplanted. 



Seeding tree. A tree sufficiently mature to produce fruit. 

 Seed variety. A variety that comes true from seed. 

 Sepal. One of the divisions of the calyx. 

 Serrate. Saw-toothed (e.g. leaves of Balm of Gilead). 

 Sessile. Without stalk. 

 Sheath. In pines, the case-like part surrounding the base of the 



needle cluster. 



Shrub. A wood}' plant with no main stem or trunk; a bush. 

 Silver grain. Bands or plates of medullary rays exposed radially 



on longitudinal section. 



Simple. Composed of one part, not compound. 

 Sinuate. Strongly wavy. 

 Sinus. An indentation. 



Solar-pit. A pit for rooting cuttings by the sun's heat (page 105). 

 Spatulate. Shaped like a spatula: broadly rounded at the apex, 



tapering toward the base. 

 Species. A division of a genus the plants of which seem to bo 



derived from an immediate common ancestor. 

 Species class. A group of trees of the same species made in forest 



survey. 



Specific gravity. Weight compared with distilled water at 4 de- 

 grees Centigrade. Where used here with reference to wood 



it refers to absolutely dry wood unless otherwise noted. 

 Spike. A simple, dense, raceme-like inflorescence with flowers 



sessile or nearly so. 

 Spore. A reproductive body, commonly applied to those borne by 



plants that do not produce seed. Analogous but not ho- 

 mologous to a seed. 



Stamen. Pollen-bearing organ of a flower. 

 Staminate. Said of flowers bearing stamens, but no pistils. Often 



used synonymously with male. 

 Stem. The main axis or one of the main axes of a plant. It may 



be underground or aerial. Commonly used in place of 



petiole, pedicel, and peduncle. 

 Sterile. Not fertile, not able to reproduce. 

 Stigma. The part of the pistil upon which the pollen falls and 



germinates. 

 Stipule. A leaf appendage at the base of the blade or petiole, 



not alwaj^s present (e.g. Black Willow). 



