_silicle._ A short, more or less circular, capsule of the mustard family. _silique._ A long capsule of the mustard family. _society._ An aggregation or company of plants, comprising a more or less distinct group. _sorus_ (plural sori). See _fruit-dot_. _spadix._ A spike of flowers (each flower usually minute), with a more or less fleshy axis, and usually accompanied by a spathe. _spathe._ A corolla-like or involucre-like leaf or bract (or a pair of them) surrounding or accompanying a spadix. In the calla, the spathe is the large white flower-like part. _spermaphyte_ (“seed plant”). A seed-bearing plant; one of the flowering-plant class. _spike._ A dense and slender flower-cluster in which the flowers open from below upwards. _sporangium_ (plural _sporangia_; _spore-case_). A body or receptacle holding spores. _spore._ A reproductive or generative cell; in flowerless plants answering the purpose of a seed, but containing no embryo. It may not be the direct product of fertilization. _sporophyll_ (“spore leaf”). A member or part that bears spores. _sporophyte._ The stage of the plant arising directly from the fertilized egg, and which ordinarily produces asexual spores (as the “plant” or conspicuous part of the fern or of a seed plant). _stamen._ The pollen-bearing organ of the flower, of which the essential part is the anther (usually borne on a stem or filament). _staminate._ Said of a flower that has stamens and no pistils. _stigma._ The part of the pistil (usually on a stalk or style) on which the pollen germinates; it is sticky, rough, or hairy at maturity. _stipel._ A stipule of a leaflet. _stipule._ A leafy or scale-like appendage at the base of a petiole. Stipules are usually two in each case. _stomate_, _stoma_ (plural _stomates_ or _stomata_). The openings on leaves and green parts through which gases pass; diffusion-pores or “breathing-pores.” _stone-fruit._ A drupe. _strict._ Said of a stem that grows straight up, without breaking into branches. _style._ The stalk between the ovary and the stigma; sometimes not present. _syngenesious._ Said of anthers when they cohere in a ring, as in the Compositæ, the style usually being inclosed. _tap-root._ A single or leading strong root that runs straight down into the earth. _tendril._ A slender coiling member of a plant that enables it to climb. A tendril may represent a branch, a petiole, a leaflet, a stipule, an entire leaf. _terminal._ At the end; as a flower borne on the end of a shoot. See _lateral_. _thyrse._ A compound, usually elongated or pyramidal flower-cluster in which the mode of inflorescence is mixed. _torus._ The end of the flower-stalk (usually somewhat enlarged) to which the flower-parts are attached; receptacle. _transpiration._ Evaporation or loss of water from plants.