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