Glossary - general

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Sac – small pouch

Saccate – pouch-shaped

Sagittal – median line in bilateral symmetry

Sagittate shape – triangular, at the base with two acute lobes, like an arrow-head

Salicoid leaf tooth – with the medial vein ending in dark (yet not opaque) persistent spherical callosity, not associated with lateral veins; a single medial vein reaching the apex of the tooth and terminated by a persistent spheroidal gland

Saline – salty, containing sodium chloride

Salver-shaped calyx or corolla – with a slender tube and an abruptly widening limb of free petal or sepal lobes spread flat

Samara – an indehiscent single-seeded fruit with a wing

Samaroid fruit – pseudosamara; resembling a samara

Sapling – a very young tree

Saprophyte – plant living on decaying vegetable matter through the intermediary of fungi; more accurately known as achlorophyllous mycotroph; readily identifiable by lack of leaves and chlorophyll

Saprophytic – obtaining all nutrition from decaying matter

Sapwood – new living outer wood, as distinct from the inner heartwood

Sarcocarp –succulent fleshy part of a stone fruit or drupe

Sarcomesotesta – a fleshy mesotesta

Sarcotesta – a fleshy testa or layer of the testa, usually mesotestal in origin and outside the sclerotesta

Sarmentose – (1) with long thin rubbers or rhizomes; (2) (of lianas) with long whip-like branches

Saxicolous – growing on rocks, lithophyte

Scabrate tectum (of pollen grains) – with elements of ornamentation of any shape smaller than 1 µm in all directions

Scabrid, scabrous (of indument) – rough to the touch, usually from the presence of minute stiff hairs

Scabridulous, scaberulous (of indument) – slightly rough, minutely scabrid

Scalariform – like a ladder

Scalariform axial parenchyma – parenchyma in fairly regularly spaced fine lines or bands, arranged horizontally or in arcs, appreciably narrower than the rays and with them producing a ladder-like appearance in cross-section; the distance between the rays is greater than the distance between the parenchyma bands

Scalariform lateral vascular pitting – pits with the lateral length equalling a wall face, either on vessel-vessel interfaces or on vessel-ray interfaces

Scalariform pit – with an elongate outline

Scalariform tertiary venation – with the tertiary veins arranged in parallel

Scale – (1) a type of indumentum in the form of small peltate scarious discs; (2) reduced leaf, usually sessile and scarious and seldom green (confer perula or bract)

Scalloped – crenate, notched with regular rounded teeth

Scandent – (1) climbing; (2) climbing without twining or use of tendrils (scrambling or rambling)

Scanty paratracheal parenchyma – occasional parenchyma cells associated with the vessels or an incomplete sheath of parenchyma around the vessels

Scape – a leafless floral or inflorescence stalk arising from ground level; naked peduncle

Scapiflorous inflorescence – with flowers borne on a scape

Scapigerous – bearing a scape

Scarious, scariose – thin and dry, not green (e.g. in Caryophyllaceae)

Scented – perfumed, smelling sweetly

Schizocarp – fruit splitting into single-seeded portions (mericarps)

Schizocarpic, schizocarpous – adjective of schizocarp

Schizogenous aerenchyma – formed by separation of cells without collapse

Schizogenous cavity – formed by the separation of cell walls of adjacent cells

Schizolysigenous cavity – formed by an initial schizogenous type of development followed by a lysigenous breakdown of cells

Sciadioid – a closed umbel (with terminal flower)

Sciadium – an open umbel (without terminal flower)

Scimitar-shaped – curved and with a sharp apex widened to one side

Sclereid – a fairly short sclerenchyma cell, usually developed when the wall of a parenchyma cell undergoes secondary thickening and, often, lignifications; the simple pits of sclereids are often more conspicuous than those of fibres; sclereids are often present as idioblasts in other tissues

Sclereid nest – sometimes large (up to several mm in diameter) aggregation of sclereids, occurring in different types of tissues

Sclerenchyma – tissue consisting of cells with thick lignified secondary walls and without cytoplasm at maturity; strengthening tissue composed of fairly short cells, sclereids, and/or relatively long ones, fibres, with thick, often lignified, cell walls and usually without a living protoplast at maturity; sclerenchyma cells usually possess simple unbordered pits; sclerenchyma may form by sclerification of the secondary walls of parenchyma cells (often involving lignifications) or it may develop directly from meristematic tissue

Sclerenchymatous endocarp – composed of thick-walled cells

Sclerified organs – having become fibrous, i.e. having developed sclereids

Scleroendotesta – a sclerenchymatous endotesta

Sclerophyllous – with small leathery leaves with thick cuticles; usually an adaptation to dry conditions

Sclerotesta – a sclerenchymatous layer of the testa, usually mesotestal in origin and inside the sarcotesta

Sclerotic – hardened, stony in texture

Scopiform – shaped like a broom, with several closely set, upward-pointing stems

Scorpioid cyme – cincinnus; a monochasial cymose inflorescence branching alternately from a bracteole/prophyll on one side of a pedicel and then from one on the other side, the flowers being borne in two rows, the whole more or less zig-zag but also coiled like the tail of a scorpion

Scorpioid inflorescence – with the main axis of the inflorescence coiled in bud, the flowers being usually two-ranked, i.e. single flowers alternating right and left; floral branches developing on alternate sides, with the flowers strictly two-ranked (distichous)

Scrambler – plant growing upwards supporting itself on other vegetation or objects, but not twining or attaching itself

Scrambling – growing upwards through other vegetation or objects, but not twining

Scrobiculate – minutely pitted

Scrobiculate tectum (of pollen grains) – see Punctate tectum

Scrofulous – with many small scaly bodies, easily flaking off

Scurf – small scales on the epidermis

Scurfily – with small membranous scales; like dandruff

Scurfy – covered with small scales

Scutellate – round and slightly convex

Scutelliform flower – (Orchidaceae) shaped like an oval dish

Scutellum – (Poaceae) a shield-shaped structure between embryo and endosperm; a shield-like and absorbtive haustorium at the end of the cotyledonary hyperphyll in the embryo or seedling

Scythe-shaped – thin, curved and sharp at apex; falcate

Secondary – not primary; subordinate

Secondary dermatogen – additional dermatogen present in monocotyledons and Nymphaeales (ambiguous term used by some authors, i.a., Voronkina and Takhtajan)

Secondary growth (normal) – lateral growth; growth in width caused by the elongation, differentiation and maturation of cells derived from the lateral meristems

Secondary meristem – see Cambium

Secondary phloem – produced towards the outside (centrifugally) by the vascular cambium; consisting of sieve elements (sieve cells and sieve tube members), parenchyma and often sclerenchyma

Secondary pollen display, secondary pollen presentation – the pollen is presented to pollinators by floral structures other than the anthers; secondary pollen display may be passive or active; nine types were identified by Howell & al. (1993): (1) enveloping bloom presenters (Araceae); (2) perianth presenters (Ericaceae); (3) androecial presenters (Santalaceae); (4) terminal stylar presenters with passive pollen placement and concealed stigmas (Proteaceae, Rubiaceae); (5) terminal stylar presenters with passive pollen placement and subterminal stigmas (Marantaceae, Polygalaceae); (6) terminal stylar presenters with active pollen placement (Asterales); (7) subterminal stylar presenters (Campanulaceae, Cannaceae, Fabaceae, Myrtaceae); (8) exposed stigmatic presenters (Rubiaceae); and (9) indusial stigmatic presenters (Goodeniaceae)

Secondary septa (pl. septum) – structures delimiting secondary cavities (e.g. secondary locules in ovaries or anthers of some plants)

Secondary wood – see Secondary xylem

Secondary woodiness – ray cells are predominantly upright (not horizontal) if there is secondary woodiness

Secondary xylem – produced towards the inside (centripetally) by the vascular cambium; consisting of the axial (vertical) system derived from fusiform initials of the cambium and including tracheary elements and fibres, and the ray (horizontal) system derived from the ray initials of the cambium and including ray parenchyma producing rays

Secreting – producing substance, usually a liquid (by glands or glandular cells)

Secretion – substance produced by glands or glandular cells

Secretory canals – internal channels (ducts) holding secretion

Secretory stigma – see Wet type stigma

Secretory tapetum (cellular tapetum, glandular tapetum, parietal tapetum) – the microsporocytes fill the centre of the anther locule, which is enclosed by a tapetal cell layer; as the microsporocytes separate, the tapetal cells enlarge, yet do not penetrate the spaces between the microsporocytes; the tapetal cells remain in their original position projecting into the anther locule, but release their secretory content into the locule

Sectile pollinium – (Orchidaceae) the condition in which soft, granular pollinia are subdivided into massulae, these usually being connected by elastic material

Secund (e.g. of leaves on a stem) – all directed to the same side

Seed – the organ by which angiosperms disperse, produced from a fertilized ovule, consisting of an embryo and usually a seed coat, with endosperm; reproductive part of a fruit

Seedling – juvenile plant arisen recently from the seed

Segmentiform – (Euphorbiaceae) shaped like a segment of an orange

Segregating – splitting off

Semi- – half

Semi-amplexicaul – of a leaf base, when the auricles extend to the other side of the stem, but without meeting

Semi-circular – half-circular

Semi-craspedodromous venation – with a single primary vein, the secondary veins branching just within the margin, one branch from each terminating at the margin and the other forming a marginal loop and joining the superadjacent secondary vein

Semi-dichotomous venation – not completely dichotomous (see Dichotomous venation)

Semilunar – crescent-shaped

Seminal – usually related to the seed

Senile – past maturity, aged and about to die

Semitectate pollen grain – with a partially discontinuous tectum in which the tectal perforations are equal to or wider than the muri and usually larger than 1 µm in diameter

Sensitive leaf or flower – reacting to touch with movement, e.g. as rachis and leaflets of Mimosa pudica

Sensu lato (s. lat., s.l.) – in a broad sense; usually in the application of a name to an aggregate species in which some authors might recognize several more narrowly delimited species

Sensu stricto (s. str., s.s.) – in a narrow (strict) sense

Sepal – a single part of the outermost whorl of floral organs, the calyx, usually green, protecting the corolla in bud

Sepaloid – resembling a sepal

Septal nectary – (monocotyledons) a nectary consisting of a complexly organized epithelial surface in the septum or septal radius of the ovary in monocotyledons where intercarpellary fusion is postgenital (carpels initially free)

Septate – divided by one or more partitions

Septenate – growing together in sevens, i.a. leaflets from one point

Septicidal capsule – placenticidal capsule; dehiscent along the lines of junction of the carpels, i.e. along the septa (placental radii), the fruit valves remaining attached and not falling off; dehiscing down the middle of the septa or partitions between the loculi

Septifragal capsule – dehiscent along the septa (the junction of the carpels) with the valves falling off; dehiscing with the valves or backs of the carpels breaking away leaving the septa intact

Septum (pl. septa) – partition of fruit or ovary; dissepiment

Sericeous – silky, with closely appressed soft, straight hairs and with a shiny silky sheen

Serrate – toothed like a saw, with regular acute and angled teeth

Serrulate – minutely serrate

Sessile – without a stalk, attached directly

Seta (pl. setae) – a bristle, or stiff hair

Setaceous – bristle-like, narrow and stiff

Setiferous – bearing bristles

Setiform – bristle-shaped

Setose – beset with bristles

Setulose – beset with minute bristles

Sexine – the outer, sculptured layer of the exine, situated above the nexine

Shaggy – with long rough and coarse hairs

Shagreened – surface with minute nodules, like sharkskin

Sheath – a tubular organ, enveloping another organ; in e.g. Poaceae or Arecaceae, the tubular part of the leaf enveloping the stem

Sheathing – enveloping and enclosing

Shoot – an elongating stem, usually near the apex of the plant; term sometimes used for the main axis

Short shoot – brachyblast, condensed shoot with short (and sometimes few) internodes, bearing leaves in seeming clusters and/or flowers and fruits; usually on the main axis or on a long/extension shoot

Shrub – self-supporting woody plant branching at or near the ground or with several stems from the base; also used for plants with a single stem but then ‘quite short’ (<2 m)

Shrublet – undershrub, small shrub

Sieve tube plastids, sieve element plastids, sieve cell plastids – plastid in the sieve tube (sieve element, sieve cell) usually containing starch and/or protein inclusions; a large number of sieve tube plastids have been defined (Behnke 2000): Ss type (most common among angiosperms other than monocotyledons) contains globular starch grains surrounded by membrane, yet neither protein crystals or protein filaments; S0 type lacks starch or protein content; P types (most frequent among monocotyledons and Caryophyllales) contain protein inclusion(s) and usually starch: P2c types has a cuneate protein crystal but without protein filaments or starch; P2cc subtype contains only cuneate crystals; P2ccl subtype contains a cuneate and several addtional ‘loose’ protein crystals; P2cco subtype contains one to three orthogonal and many cuneate protein crystals; P2ccp subtype contains a single large loosely-packed polygonal crystal and many cuneate ones; P2cs types contains starch grains in addition to cuneate crystals: P2ccs subtype contains cuneate crystals; P2ccps subtype contains a polygonal in addition to cuneate crystals; P2cf types contains both protein crystals and filaments: P2ccf subtype contains cuneate crystals; P2clf subtype contains cuneate and loose crystals; P2ccof subtype contains cuneate and orthogonal crystals; P2ccpf subtype contains a loosely-packed polygonal crystal in addition to cuneate ones; P2cfs type contains cuneate protein crystals and filaments, and starch

Sieve plate – an area of the end wall of a sieve element; the sieve plate has larger pores than found elsewhere on the wall, the pores being open channels

Sieve tube – a conducting tube in the phloem made up of a number of sieve elements attached end to end

Sigmoid – doubly curved in opposite directions like an S

Silica – silicon dioxide

Silica bodies – crystals of silica occurring inside plant cells

Silica cell – (Poaceae) cells in the epidermis containing silica deposits

Siliceous – containing silica

Silicula (pl. siliculae), silicule – short siliqua, but less than three times as long as wide

Siliqua (pl. siliquae) – a fruit divided into two cells by a thin partition, opening by two valves which fall away from a frame on which the seeds are borne; more than three times as long as wide; e.g. in Brassicoideae

Siliquiform – (Capparoideae, Cleomoideae) shaped like a siliqua

Simple – (1) (of leaves) not divided into leaflets (as opposed to compound); (2) (of inflorescences) with only one order of branching; (3) (of fruits) resulting from the ripening of a single ovary, as opposed to compound fruits (derived from more than one flower)

Simple cyme – an inflorescence with pedicels of equal length

Simple perforation plate – end walls of a vessel element being completely broken down thus leaving a single aperture (opening)

Simple pit (of vascular tissues) – with the opening as wide as the base

Simple polyembryony – several embryos develop in each ovule due to the development of several fertilized egg cells

Simplicolumellate – simplibaculate; with a single row of columellae (bacula) below each murus – Opposite: duplicolumellate, pluricolumellate

Simultaneous microsporogenesis – the cytoplasm is subdivided only after completing the two meiotic division, either by centripetal or centrifugal wall production; this results in a large number of different types of pollen tetrads (tetrahedral, tetragonal, rhomboidal, etc.)

Sinistrorse – towards the left (when viewed from the front), e.g. in climbing stems – Opposite: dextrorse

Sinuate – with the uneven margin having fairly deep rounded sinusoidal undulations

Sinuose – (Amaranthaceae) wavy, sinuate

Sinuous – wavy

Sinus – (1) recess between the teeth or lobes of a margin; (2) angle formed by the basal lobes of a leaf

Siphonogamy – a type of fertilization, in which a pollen tube releases non-flagellated gametes directly to the egg apparatus (synergids and egg cell)

Siphonostele – a type of stele, in which the central vascular column is medullated (with a pith)

Siphonostelic stele – with a perforated (leaf gaps) hollow vascular cylinder of xylem and phloem

Solanad embryogenesis – a linear tetrad is formed in the proembryo; the derivatives of the basal cell do not take part in the organization of the embryo, this being derived mainly from the apical cell of the two-celled proembryo

Soleiform – slipper-shaped or almost like an hourglass

Solenostele – a type of stele with a central core (of pith) surrounded by rings of phloem, xylem, and phloem again

Solitary (usually of stem) – single; not in clusters – Opposite: clustered, suckering

Somatic chromosome number – with twice the haploid number (n); 2n

Sorosis – a fleshy fruit formed by the consolidation of numerous flowers together with their receptacles, ovaries and other structures (e.g. mulberry, pineapple, breadfruit)

Spadix – unbranched inflorescence with fleshy or thickened axis in which the flowers are (partly) sunken, as in Araceae

Spathaceous – resembling, or with the function of, a spathe; e.g. large bract(s) enclosing the flower(s)

Spathe – large sheathing bract, usually either the prophyll or a peduncular bract, surrounding the inflorescence or spadix

Spathella – a small closed membranous sac-like structure which envelopes the immature flower and ruptures irregularly when the pedicel elongates at anthesis (in, e.g., some Podostemaceae)

Spatheole – (Poaceae) the bladeless sheath subtending the inflorescence; or the modified leaf sheath encasing part of the inflorescence

Spatulate, spathulate, spathuliform – shaped like a small spatula: oblong, with an extended slender basal part

Spheroid – three-dimensional shape, like a sphere

Spheroidal – shaped like a sphere

Spicate inflorescence – spike-like; unbranched, the flowers (seemingly) borne directly on the axis

Spiciform – resembling a spike

Spicoid – the ultimate inflorescence unit in Cyperaceae tribes Hypolytreae and Chrysitricheae, with a much reduced axis and appearing like a flower; it comprises two to twelve floral bracts, each subtending a male flower; the whole structure is terminated by a female flower, thus making it determinate

Spicoid bract – (Cyperaceae) a glume-like bract which subtends the spicoid

Spiculate – covered in minute spines

Spike – (1) a racemose inflorescence with the flowers sessile along a common unbranched axis; flowers single or (less precise) in short clusters; (2) (Cyperaceae) an aggregation of spikelets or spicoids; sometimes the whole structure is similar in appearance to a spikelet

Spikelet – (Cyperaceae, Poaceae etc.) elongated or reduced axis with one to many glumes, each glume subtending a bisexual or unisexual flower

Spindle-shaped – see Fusiform

Spindly – thin

Spine – a sharp-pointed, hardened structure generally derived from stipule or leaf

Spinescence – spininess

Spinescent – more or less spiny; ending in a sharp point

Spine shield – horny pad from which the spines stick out (in e.g. Euphorbia)

Spiniform – spine-shaped, thorn-like

Spinose – with spines; mostly used for leaf margin

Spinose leaf tooth – with the principal vein projecting beyond the non-glandular apex

Spinous – with spines

Spinulate tectum, spinulose tectum (of pollen grains) – with small spinuli, less than 3 µm in height

Spinulus – a pointed projection less than 3 µm in height

Spiny – armed with spines

Spirally arranged organs – arranged in a spiral or ascending coil along an axis, e.g. of leaves on a stem with one leaf per node; alternate

Spiraperturate pollen grain – with a single spiral aperture winding in spiral over the pollen surface

Spiromonostichous – borne in a single rank in a spiral along the axis

Split lateral node (common gap type) – in some plants with opposite leaves, when single leaf traces departing from the central vascular cylinder at the midpoints between the two leaves divide into two, one part proceeding to each leaf

Spongiose – spongy, soft

Sporopollenin – the acetolysis resistant biopolymers which make up most of the material of the exine

Sprawling habit – spreading loosely, not erect

Spur – (1) a tapering projection, usually short and curved; (2) a short shoot of the stem bearing leaves and/or flowers and fruit; (3) (of flowers) a slender hollow extension usually of the perianth, and often containing nectar

Spur shoot – a short, compact branch usually lateral to the main axis, with very short internodes, bearing leaves and/or flowers and fruit; brachyblast or short shoot

Spurred – bearing a hollow slender projection or extension

Squamula intravaginalis – see Intravaginal squamules

Squamiform – shaped like a scale

Squamulose – beset with small scales

Squarrose – rough with tips of scales/bracts etc. projecting outwards

Stachyoid – a closed spike (with terminal flower)

Stachyum – an open spike (without terminal flower)

Stamen – the male organ of a flower, the male sporophyll, consisting of a stalk (filament) bearing the connective and container(s) (anthers) which bear the pollen

Staminate – (1) (of flowers) bearing stamens; (2) (of plants or flowers) male

Staminode, staminodium – a sterile or abortive stamen, usu. not bearing pollen; sometimes smaller than the fertile stamens, sometimes (i.a. in Malvales) larger

Staminodial – adjective for staminodium

Standard (of flower) – (e.g. Faboideae) the large upper/posterior petal (outside in the bud); vexillum

Staurocytic stomata – guard cells surrounded by (three or) four (or five) similar subsidiary cells with anticlinal walls arranged crosswise to the guard cells, the subsidiary cells being radially elongated; with (three or) four (or five) subsidiary cells each oblique to the long axis of the guard cells

Stegma – an idioblast containing silica; the cell wall adjacent to the sclerenchyma beneath is thick, the anticlinal walls are thinner and the outer periclinal wall is thinnest

Stele – the part of a plant axis made up of the primary vascular system and its associated ground tissue (the pericycle, the medullary rays and the medulla)

Stelidium (of flowers) – (Orchidaceae) the teeth of the column in Bulbophyllum

Stellate, stelliform – star-shaped, with numerous arms radiating outwards (e.g. stellate hairs)

Stellate hair – star-shaped hair (as seen from above)

Stellulate – diminutive of stellate; small and star-shaped

Stem – the main axis of a plant, bearing roots, leaves and/or flowers

Stephanocytic stomata – with weakly differentiated subsidiary cells that are arranged in a rosette; surrounded by four or more weakly differentiated subsidiary cells; the guard cells surrounded by four or more weakly differentiated subsidiary cells

Stereome – (Asteraceae) a part of the phyllary which is (semi-)transparent

Sterile (of sexual organs or structures) – barren, not functional

Stigma – the pollen receptor on the gynoecium, either sessile on the ovary or on top of the style; the stigma may be canaliculated, decurrent, expanded, punctate, etc.

Stigmatic – relating to the stigma

Stigmatic knob – the knob-shaped stigma, or stylar head on which a stigma sits

Stigmatic surface – that part of the style/pistil receptive to pollen; the stigmatic surface may be Dry type or Wet type; the stigmatic receptive surface may be papillate or non-papillate, or concentrated to multicellular hairs or papillae

Stigmatoid tissue – pollen-transmitting tracts, transmitting tissue; one- or several-layered tissue present on the stigma and inside the style lining the stylar canal and on the placenta inside the ovary, sometimes also on the funicle; in some species the stigmatoid tissue is brought close to the micropyle by a placental proliferation in the form of a small protuberance, the obturator; the stigmatoid tissue supports the growth of the pollen tubes

Stigmatose – provided with stigmas; or with conspicuous stigmas

Stilt roots – prop roots, buttresses, plank buttresses; lateral adventitious roots from the lower (proximal) part of the stem, reaching the ground and supporting the plant

Stinging hair – tubular hair filled with irritant liguid which, upon breaking, eject the liquid causing itching or blistering of skin (in, e.g., Urticaceae)

Stipe – (1) (Arecaceae) an individual stem or trunk of a clustering palm; (2) the stalk inside the flower or fruit which supports the carpel(s) or gynoecium; (3) (Orchidaceae) a pollinium stalk (stipites), which is derived from the rostellum; (4) (Cyperaceae) short, narrowed extension to the base of the nutlet

Stipellate – with stipels

Stipels – stipule-like outgrowths occurring in pairs at the base of a leaflet in some compound leaves

Stipitate – supported on a special stalk

Stipitiform – shaped like a long narrow cylinder

Stipulate – with stipules

Stipule – leaf-like, spine-like or scale-like appendage of the leaf, usually in pairs at the base of the petiole

Stipuliform – shaped like a stipule

Stolon – (1) vegetative shoot spreading along the surface of the ground; a runner which roots; (2) (Cyperaceae) a thin underground branch arising from the rhizome or base of the culm; each stolon terminates in an aerial shoot

Stoloniferous – bearing stolons; with runners or propagative shoots rooting at the tip producing new plants

Stoma (pl. stomata) – leaf pores, used for transpiration; breathing pores in the leaf epidermis enclosed by a pair of guard cells

Stone – hard endocarp of a drupe

Stone cell – see Brachysclereid

Straggling – growing irregularly and untidily

Strap-shaped – narrow, with straight margins; ligulate, lorate

Strasburger cell – albuminous cell which (although closely linked functionally with the sieve cell) are not formed from the same mother cell

Stratified – in distinct horizontal layers

Stratified phloem – secondary phloem in which there are bands of fibres alternating with normal phloem tissue

Striae – slightly sunken stripes or lines

Striate – with parallel longitudinal grooves

Striate pollen grain – with elongated, usually parallel elements separated by grooves

Striation – a fine groove

Strigillose – with small, sharp, straight bristles; hispidulous

Strigose – with sharp stiff hairs laying close to the surface

Strigulose – with short and sharp stiff hairs laying close to the surface

Strobilate inflorescence – when resembling a cone in being covered by imbricate scales

Strobiliform – cone-shaped

Strobilus (pl. strobili) – an inflorescence largely made up of overlapping scales

Strophiolate – with strophioles

Strophiolus – strophiole; an outgrowth of the outer seed integument, near the hilum; usually small and fleshy, and associated with animal dispersal; also called a carunculus, but a strophiolus is an outgrowth from the raphe, whereas the carunculus is adjacent to the micropyle

Stunted – of less than normal stature; dwarfed

Stylar arm – branch of the style

Style – the part of the gynoecium between the ovary and the stigma (often slender); style solid (i.e. filled with pollen tube transmitting tissue) or hollow

Stylode, stylodium – free (not connate) styles of an otherwise syncarpous pistil

Styloid – a crystalline form of calcium oxalate consisting of elongated usually single crystals found as inclusions of cells; the styloids have pointed or square ends and are at least four times longer than wide

Stylopodium – when more than one style is present a structure just above the ovary or avaries composed of the connate proximal parts of the styles (i.a. in Apiaceae)

Stylule, stylulus – an elongated part of an individual free (not connate) carpel down which pollen tubes grow exclusively to that carpel

Sub- – (1) nearly, almost; (2) below, under, beneath

Subangulaperturate pollen grain – an almost subangulaperturate pollen grain

Subapical placentation – nearly apical placentation

Subbasal placentation – nearly basal placentation

Subcampylotropous ovule – an almost campylotropous ovule

Subcapitate stigma – an almost capitate stigma

Subcordate – slightly notched, but not as much as cordate

Subepidermal – pertaining to layers beneath the epidermis

Suberin – cell wall component of, e.g., cork layer, endodermis, which consists of polyphenolic compounds with a considerable amount of hydroxycinnamic acids and their derivatives and a network of glycerol-bridged polyesters

Suberin lamella – a thin layer of material (largely suberin) usually deposited on all internal faces of a primary wall in the exodermis and/or endodermis of a root; possibly restricting the transport of water and minerals across the bundle-sheath/mesophyll interface

Suberose – corky

Subfibrous endotegmen – somewhat fibrous

Subhilum – region beneath the hilum in the seed

Subintrorse anthers – almost introrse anthers

Subinvolute ptyxis – an almost involute ptyxis

Sublaminar placentation – almost laminar placentation

Subligneous – more or less woody

Sublocular floral part – sublocular region; part of the ovary situated below the locules (the locular part)

Submarginal placentation – almost marginal placentation

Submerged – present under water

Subopposite – almost opposite

Suborthotropous ovule – almost orthotropous ovule

Subpachycaul – more or less pachycaul

Subpalmate venation – almost palmate venation

Subplicate ptyxis – an almost plicate ptyxis

Subquadrate – almost square

Subshrub – small shrub with partially herbaceous stems

Subsidiary cell (of stoma) – additional modified cell lying outside the guard cells; subsidiary cells are usually different from ordinary epidermal cells

Subspheroidal pollen grain – the ratio between the polar axis and the equatorial diameter is 0.75–1.33

Subtended – axillary to another organ below the organ under discussion

Subtending – standing below and close to another organ, as a floral prophyll (bracteole) to a flower

Subterranean – underground

Subtruncate – almost trunctate

Subulate – awl-shaped, like a stout needle; linear-lanceolate

Subumbellate – almost umbellate

Successive cambia – a series of vascular cambia, alternating with conjunctive tissue, are initiated sequentially from a master cambium (a lateral meristem), each one producing phloem to the outside and xylem to the inside (and other tissues)

Successive microsporogenesis (cytokinesis) – the cytoplasm is subdivided after each of the two meiotic divisions; confined to cell wall formation via centrifugally developed cell plates and tetragonal (or as isobilateral, decussate, T-shaped or linear) pollen tetrads

Succose – juicy, sappy

Succulent – (1) (adjective) juicy, pulpy; (2) (noun) a plant with thick, fleshy and swollen stems and/or leaves, usually adapted to dry or salt environment

Sucker – a shoot arising from the roots below ground, usually some distance from the main stem

Suckering – producing suckers

Suffretescent – like a subshrub, somewhat shrubby

Suffrutex – subshrub; often, more specifically, a plant producing annual shoots from a woody subterranean base

Suffruticose – adjective of suffrutex

Suffused – spread throughout with colour

Sulcate – grooved, furrowed

Sulcatoporate pollen grain – intermediary between sulcate (colpate) and porate

Sulcoidate pollen grain – indistinctly sulcate

Sulculate pollen grain – with elongate simple latitudinal apertures not situated at the poles

Sulcus (of pollen grains) – an elongated latitudinal ectoaperture present at the proximal or distal pole

Super-, supra- – above

Superior ovary – when the sepals, petals and stamens are inserted below the ovary (hypogynous); also when the receptacle bearing the calyx, corolla and stamens is expanded into a hypanthium

Superposed cotyledons or corm – unequal

Supervolute ptyxis – both sides very strongly curved adaxially, one margin overlapping the other; the ptyxis in monocotyledons is usually supervolute or supervolute-curved

Suppressed – not clear, vestigial but presumed to have been present in ancestors

Supra-axillary – growing above an axil, not in it

Supratectal pollen grain – with processes such as spines present on top of the tectum

Suspensor – a part of the proembryo; the suspensor is derived from the basal (micropylar) cell of the bicellular embryo

Suture – the line of a junction, or seam of union, commonly used of the line of opening of a carpel; dorsal suture (outer or anterior) thought to represent the midrib of the carpellary leaf; ventral suture (inner) thought to represent the united margins on which the ovules and placentas are borne

Syconium (pl. syconia) – syconus; a multiple (composite) fruit developed from an invaginated inflorescence axis with a hollow centre, which is lined with minute achenes or drupes, present in, e.g., Ficus

Syconus – see Syconium

Sylleptic branch – a branch formed by continuous development from an axillary bud primordium; with well developed internode, hypopodium, below prophylls

Sympetalous flower – having the petals united; gamopetalous

Sympodial (of sympodium) – without a single main stem

Sympodium – stem made up of a series of superposed branches, these imitating a single main axis: each new shoot developing from an axillary bud on the previous shoot unit; stem where growth is continued not by the main stem but by lateral branches; sympodial inflorescences include the cyme, dichasium, rhipidium, cincinnus and false umbel; monopodial inflorescences include the raceme, true umbel and corymb

Sympodium (of vascular tissues) – an axial vascular bundle and its leaf trace and branch trace

Synandrium – the cohesion of the anthers of each male flower

Synandrodium (pl. synandrodia) – (Araceae) compressed sterile flowers

Synanthous – with flowers and leaves appearing simultaneously

Syncarp – a multiple fruit produced by the cohesion of the individual fruits from several flowers

Syncarpous flower – with connate (fused) carpels, as distinct from apocarpous

Syncarpy – with gynoecium consisting of connate carpels

Syncolpate pollen grain – with two or more simple colpi the ends of which anastomose at the pole

Syncolporate pollen grain – with two or more compound colpi the ends of which anastomose at the pole

Synergid (of megagametophyte) – one of the usually two cells which are closely associated with the egg cell in the egg apparatus at the micropylar end of the megagametophyte; the synergids are involved in the fertilization of the egg cell

Synflorescence – (Asteraceae) a compact arrangement of capitula within a common (secondary) involucre

Synflorescence polytele – the inflorescence system where the inflorescence axes fail to terminate in flowers

Synsepalous – with more or less connate sepals

Syntropous ovule – the ovule is curved (anatropous) in the direction of carpel curvature, corresponding more or less to apotropous