SEBACEOUS: Having the appearance of fat, as the sebaceous secretions of some plants.
SEBIFEROUS: Sebaceous; greasy.
SECTILE: Referring to pollinia in loosely coherent "packets".
SECUND: To one side, as flowers on an inflorescence.
SEDGE PEAT: The peat that results from decaying masses of several types of mosses.
SEDIMENTARY ROCK: Rock composed of particles deposited from suspension in water, like sandstone, limestone, shale and conglomerates.
SEED: The ovules of flowering plants (except those of gymnosperms such as Pines) are contained within an ovary. Pollen grains come in contact with the stigma, germinate and send down long tubes through the style into the ovary. These pollen tubes contain nuclei which fuse with the nuclei of the ovules and fertilization is effected. The ovules then form seeds. Seeds consist of a seed coat (testa), two seed leaves (cotyledons) or one seed leaf, and the embryo plant. The embryo consists of a root and a shoot. At the end of the seed is a scar (hilum), where the seed was attached to the pod. Near this scar is a microscopic hole (micropyle) where the pollen tube entered to fertilize the ovule and through which the root emerges when germination takes place.
SEED LEAF: A cotylendon, which is the beginning leaf or leaves in an embryo.
SEEDLING GUARD: A row cover to protect seeds or new sprouts indoors or out.
SEED VESSEL: The pericarp, or wall of the ripened ovary, which contains the seeds.
SELF: 1. An individual plant produced by self-fertilization, as opposed to cross-bred. 2. A self-colored flower, of a single color.
SELF-COLORED: Uniform in color, as self-colored flowers.
SELF-FERTILE/SELF-POLLINATE: A plant's ability to fertilize its pistils with its own pollen.
SELF-FERTILIZATION: The fertilization of a flower by pollen from the same flower. (Compare to cross-fertilization.)
SELF-SEED: A plant releases ripe seeds that sprout into new plants without help from the gardener.
SELF-STERILE: A plant's inability to fertilize itself, as a self-sterile flower; opposite of self-fertile.
SEMI-ADHERENT: Having the lower half adherent, as a seed, stamen, etc.
SEMI-AMPLEXICAUL: Half-amplexicaul; embracing half of the stem, as many leaves.
SEMI-AQUATIC: Living in or close to water, as semi-aquatic plants that grow between tides, or in pools that become dry every so often.
SEMI-DOUBLE: This describes flowers that have one two or more rows of regular, irregular, or loose petals and conspicuous stamens.
SEMINIFEROUS: Seed-bearing; producing seed.
SEMPERVIRENT: Always green or fresh; evergreen.
SEPAL: Each segment of the calyx. Though usually plain and green, it may sometimes be ornate. The outermost whorl of flower parts.
SEPALODY: The transformation of petals or other organs into sepals.
SEPARATE (noun): One of the individual size groups of mineral soil particles; sand, silt, or clay.
SEPT- or SEPTI-: Seven, as in septifolius - seven-leaved.
SEPTATE: Divided by or having a septum or partition.
SEPTILE: Belonging to or relating to septa (see entry below).
SEPTUM (pl. septa or septums): A partition or dividing wall, as the septum in a compound ovary or fruit.
SERICEOUS: Silky.
SEROTINAL: Appearing or occurring in the later part of the summer.
SERPENTINE ROCK: A rock consisting of acid magnesium silicate.
SERRATE: Leaves and other plant parts that have sharp "teeth" along their edges pointing toward the tip.
SERRULATE: Finely serrate; denticulate.
SESSILE: Leaves and other plant parts that have no stalk, but instead grow directly from the stem of the plant.
SETACEOUS: Having or consisting of bristles, or resembling a bristle; setiform.
SETIFORM: Bristle-like.
SETOSE: Bristly.
SETULA: A short seta, bristle, or hair.
SETULOSE: Finely setose; covered with small hairs or bristles.
SEWAGE SLUDGE: An organic fertilizer that consists of dried processed sewage.
SEXFOIL: A leaf with six leaflets; a flower with six perianth segments.