Sepal  : member of calyx. outermost part of flower; usually green. 

Sessile : without a stalk. 

Shrub : a woody perennial plant smaller than a treen and usually with several basal stems 

Species : a term for all the individuals of one kind. 

Spherical = globose : a 3 - dimensional solid, round in outline, like the earth. 

Spore (fern ) : reproductive body of lower plants, usually single cell. 

Stamen : male organ of flower, consisting of filament (stalk) and anther containing pollen. 

Sterile : infertile and unproductive, as a flower without a pistil, a stamen without an anther or a leafy shoot 
without  flowers. 

Stigma : sticky or feathery area above ovary, receiving pollen at pollination. 

Stipule : leafy outgrowth, often paired, arising at the base of the leaf stalk. 

Style : the usually stalk-like part of a pistil connecting the ovary and stigma. 

Substrate : material in or on which plant is growing, e.g. soil, rock, sand. 

Scaberulous: covered with small hard rough hairs. 

Scandent: climbing. 

Scutellum: a second and anterior cotyledon in grasses, as in wheat. 

Sessile: without stalk. 

Setaceous: with long, stiff needle-like hairs. 

Sinus: a recess or re-entering angle. 

Soriferous: bearing sori,i.e. the reproductive organs in ferns. 

Spadix: a flower spike with a fleshy axis. 

Spathe: a more or less modified bract encloseing an inflorescence. 

Spiciform: a spike-like inflorescence. 

Spike: an inflorescence with sessile flowers on a usually elongate axis. 

Spikelet: an ultimate part of a spike with 1 or more sessile flowers. 

Staminode: an abortive stamen without anther and pollen. 

Standard: referred to the prominent flag-like petal in the pea-family (papilionaceae) 

Stellate: star-like, usually referred to hairs on plant parts. 

Stigma: the terminal part of pistil which receives the pollen. 

Stipitate: stalked. 

Stipule: a lateral appendage at the base of the petiole. 

Strobilate: an inflorescence largely made up of overlapping bracts, like a pine-cone. 

Sulcate: grooved or furrowed. 

Superior: situated above other parts; usually referred to the position of a ovary in a flower. 

Sympodial: a stem with a series of superposed branches appearing to be a simple axis. 

Syncarpous: composed of two or more united carpels.