Glossary - general
[ A B C D E F G H I J K L M N O P Q R S T U V W X Z ]
Abaxial – the side of an organ that faces away from the axis bearing it (i.a. the lower surface of a leaf) – Opposite: adaxial
Abortion – suppression/reduction of parts which are usually present, partway through their development (usually of flowers or fruits)
Abortive – imperfectly developed, not grown to its normal size or function
Abruptly pinnate – a pinnate leaf without an odd terminal leaflet; the term paripinnate is preferred
Abscission (of leaves or rarely branches) – detaching from the stems bearing them at a predetermined place, the abscission zone
Acalymmate pollen tetrad – tectum not crossing the junction between tetrads
Acanthophyll – (Arecaceae) leaflet of a pinnate leaf modified in the form of a spine
Acarodomatia – small pockets in leaves, in the axils of the veins on the abaxial surface, theoretically harbouring mites (Acari); usually contracted to ‘domatia’
Acaroid resin – (Xanthorrhoeaceae) reddish to yellowish resin, forming an insoluble, hard and very resistant layer at high temperature
Acarpellate – without carpels – Opposite: carpellate
Acaulous – without a (visible) stem
Accessory branch – secondary branch
Accessory fruit – false fruit, conspicuous but without other function than attraction
Accessory bud – additional to axillary buds, and assuming their function
Accrescent – increasing in length or thickness with age (e.g. the calyx after flowering)
Accumbent – lying against (i.a. the cotyledons against the radicula)
Accumbent embryo – folded in a way so that the radicula is directed against the edges of the two cotyledons; the cotyledons in an embryo developed from a curved ovule (accumbent embryo) are in the plane formed by the longitudinal axis of the seed and the chalaza
Acetabuliform (of nectariferous disc etc.) – (Euphorbiaceae etc.) saucer-shaped
Achene – a small dry thin-walled fruit, indehiscent (not splitting when ripe), and containing a single seed; the term is normally used for a fruit formed by a single carpel – see Nut
Acicular – needle-shaped; very narrow, stiff, and pointed (i.a. leaf tips)
Acolumellate exine – exine without columellae (bacula)
Acolyte – (Arecaceae) sterile male flower found together with a fertile female flower as a flower pair in the inflorescence of Calamus
Acrodromous venation – two or more primary (or well developed secondary) veins diverge at or above the lamina base and run in convergent arches toward the apex; arches not curved basally
Acropetal(ous) – in the direction of the apex – Opposite: basipetal(ous)
Acropetal venation – venation developing from the base towards the apex
Actinocytic stomata – radiate-celled stomata; two guard cells surrounded by a circle of radiating subsidiary cells; with five or more somewhat radially enlarged or elongated subsidiary cells surrounding the guard cells
Actinodromous venation – three or more primary veins diverge radially from a point at or above the lamina base and proceed towards the margin
Actinomorphic flower – radially symmetrical, polysymmetrical; regular, radially symmetric
Actinostelic – uninterrupted central vascular cylinder with radiating ribs
Aculeate – armed with prickles (as distinct from thorns)
Aculeus (pl. aculei) – sharp point(s), prickle(s)
Acuminate – tapering to a long tip (usually of leaf tips)
Acute – sharp, sharply pointed, the margins near the tip being almost straight and forming an angle of <90o – Opposite: obtuse
Adapical – towards the apex
Adaxial – the side of an organ towards the axis on which it is inserted (e.g. the upper surface of a leaf) – Opposite: abaxial
Adherent (of different organs) – attached but not fused
Adjacent-ligular – (Arecaceae) germination type where the shoot is carried out of the seed within the very short ligule of the cotyledon
Adnate – (usually of different organs) attached to, surface to surface (e.g. stamen adnate to petal)
Adplicate ptyxis – flat vernation; plane
Adventitious buds – buds produced elsewhere than normal (such as from the stem instead of, as usual, in leaf axils)
Adventitious embryony – the embryo arises from the diploid megasporangium tissue which surrounds the megagametophyte
Adventitious roots – lateral roots arising from organs (e.g. the stem) other than the main root system
Aerenchyma – air canal consisting of thin-walled cells and large intercellular spaces in roots and shoots of many aquatic or hygrophilous plants, allowing the exchange of gases
Aerenchymatous – adjective of the noun aerenchyma
Aerial leaves (of aquatic plants) – leaves which are neither submerged nor floating
Aerial roots – roots emerging from the plant entirely above the ground surface
Aerial stem – a stem or part of a stem which is not submerged, floating or below the ground surface
Aestivation – the way in which sepals or petals are folded/packed in bud
Agglomerated – densely crowded, but not stuck together
Agglutinated – stuck together
Aggregated – in a dense mass, the individual parts touching
Aggregate fruit – an assemblage of fruits formed from the free (i.e. not connate) carpels of a single flower with apocarpous gynoecium
Alae – wings, lateral petals
Alate – winged
Albumen – antiquated term for endosperm, nutritive substance accompanying the embryo
Albuminous – with albumen, the nutritive substance in the seed
Aliform axial parenchyma – a paratracheal axial parenchyma in which lateral wings are present as seen in cross-section; parenchyma cells surrounding or at one side of the vessel and with lateral extensions
Allelocytic stomata – with an alternating complex of three or more C-shaped subsidiary cells of graded sizes surrounding the guard cells
Alternate – inserted at different levels of the axis
Alternate lateral wall pitting (of vascular tissue) – intervascular pits spirally distributed across the vessel elements, either on vessel-vessel interfaces or on vessel-ray interfaces
Alternipetalous – alternating with the petals
Alternisepalous – alternating with the sepals
Alternitepalous – alternating with the tepals
Altingioid leaf tooth – basically asymmetrical, with a persistent transparent gland at the apex, and with their lateral veinlets free, not reaching the medial vein
Alveolate – with pits resembling a honeycomb
Alveoli – surface cavities or depressions, like a honeycomb
Amentiferous – bearing catkins
Amentiform – resembling a catkin
Ament(um) – a slender, often pendulous, cylindrical inflorescence with crowded (sub)sessile unisexual apetalous flowers, falling as a whole after fruiting
Amoeboid tapetum – see Amoeboid-periplasmodial tapetum
Amoeboid-periplasmodial tapetum – the young microsporocytes are in the centre of the anther locule and surrounded by tapetal cells; as the microsporocytes separate, the cell walls of the tapetal cells degenerate and develop plasmodesmata which connect the protoplasts of the tapetal cells; the protoplasts fuse and form a multinucleate periplasmodium surrounding the microsporocytes/pollen tetrads; the periplasmodium is enclosed by a perispore membrane
Amphianisocytic stomata – the two guard cells are covered by four subsidiary cells in two layers at right angles (not parallel) to the guard cells
Amphibious – plants adapted to life both on land and in water
Amphicarpous – (Schoenoplectus in Cyperaceae) applied to a small secondary inflorescence occurring at the base of the culm
Amphicribral vascular bundles – with the phloem surrounding the xylem in some concentric vascular bundles – Opposite: amphivasal
Amphisarca – indehiscent multilocular many-seeded fruit, with a dry and hard outer part and a pulpy and soft inner part (i.a. a melon)
Amphitropous ovule – with the ovule apex and the stalk base next to each other and with the megagametophyte curved; attached near its middle, half-inverted, with the raphe terminating approximately half-way between the chalaza and the orifice
Amphivasal vascular bundles – with the xylem surrounding the phloem in some concentric vascular bundles – Opposite: amphicribral
Amplexicaul – embracing the stem, e.g. with the leaf base extending to the side of the stem opposite to the main blade
Ampulliform – swollen in the shape of a flask (e.g. the corolla in Erica)
Ana-amphitropous ovule – a type of amphitropous ovule, in which the trace proceeds a distance along one side of the ovule prior to reaching the megasporangium
Anacampylotropous ovule – a type of campylotropous ovule, in which the trace proceeds half-way up along one side of the ovule prior to reaching the megasporangium
Anantherous filament – without an anther
Anastomosing – forming a network
Anastomosis – union of one vein with another, the connection forming a network
Anasulcate pollen grain – with sulcus/sulci distal on the pollen grain
Anatomy – internal structure
Anatrichotomocolpate pollen grain – with three-armed colpus distal on the pollen grain
Anatropous ovule – reversed; inverted at 180o parallel to its stalk so the micropyle is close to the point of funiculus attachment
Anaulcerate pollen grain – with ulcus/ulci distal on the pollen grain
Androclinium – see Clinandrium
Androdioecious – with some plants bearing only functionally hermaphrodite flowers and other plants functionally male flowers
Androecium – a collective term for the stamens in a flower
Androgynophore – a stalk carrying both stamens and carpels/ovary above the insertion of the petals
Andromonoecious – a plant with both male and hermaphrodite flowers, but without female flowers
Androphore – a stalk on which the stamens are carried
Andropodium – a structure consisting of connate staminal bases
Anisocytic stomata – unequal-celled stomata; the two guard cells are covered by three subsidiary cells, of which one is markedly smaller than the other two; with three subsidiary cells, two large and one smaller, surrounding the guard cells
Anisophyllous – where the two opposite leaves at a node are of very unequal size or shape
Anisomorphic leaves – leaves of usually two different morphological types on the same shoot or at least on the same plant
Annual shoot – shoot sprouting from the perennial root/stem system and lasting only one growing season
Annular – in the shape of a ring; used of any organs arranged in a circle
Annulus (pl. annuli; of pollen grains) – area of exine surrounding a pore and sharply differentiated from the remainder of the exine
Anomalous – out of the ordinary, unlike others in its group
Anomalous secondary growth – secondary (lateral) growth that does not follow the normal pattern of a single vascular cambium producing xylem to the inside and phloem to the outside
Anomocytic stomata – the stoma is surrounded by a varying number of subsidiary cells resembling normal epidermal cells (the subsidiary cells with the same appearance as the guard cells); stomata lacking differentiated subsidiary cells surrounding the guard cells
Anomotetracytic stomata – the guard cells are surrounded by four irregularly arranged subsidiary cells
Anomotreme pollen grain – with irregular aperture(s)
Antepetalous (oppositipetalous) – opposite to a petal, and not alternate with it
Anterior – positioned in front, turned away from the axis
Antesepalous (oppositisepalous) – opposite to a sepal, and not alternate with it
Antetepalous (opposititepalous) – opposite to a tepal, and not alternate with it
Ant galls – inflated, ultimately woody structures from the usually fused bases of stpules in some Acacia species; hollow, an often inhabited by ants
Anther – the part of the stamen containin the pollen
Anther collar – (Asteraceae) a region of swollen or otherwise demarcated cells at the apex of the filament(s)
Anther pit – the filament tip is immersed in a narrow concavity such that the attachment point of the anther is hidden
Anther pseudopit – the thecae partially surround the filament at the attachment point of the anther but do not form a complete pit
Antheriferous – bearing anthers
Antherodes – remnants of anthers; staminodia
Anther placentoid – a placenta-like parenchymatous structure arising from the inner wall of the anther in some plants
Anthesis – time of pollination of the flower; time of receptivity of stigma, or distribution of pollen
Anthocarp – a pseudocarp formed from a single flower, the fruiting structure being covered by an accrescent perianth or calyx; in Nyctaginaceae consisting of the fruit and the perianth base
Anthophore – an elongated internode present between the sepals and the ovary and between the petals and the stamens
Anticlinal – perpendicular (at right angles) to the surface
Anticous – most distant from axis, turning away from axis
Antipode – the chalazal part of the megagametophyte
Antitropous ovule – the ovule is curved (anatropus) in the opposite direction to the carpel curvature, corresponding more or less to epitropous
Antrorse – pointing towards the distal end, upwards or forwards – Opposite: retrorse
Antrorsely – upward or forward
Anulopunctate tectum (of pollen grains) – with puncta less than 0.3 µm in diameter
Apert aestivation – see Open aestivation
Aperturate – with an opening, not closed
Aperture (of pollen grains) – specialized area of the sporoderm, which is thinner than the remaining sporoderm (usually also differing in structure and ornamentation)
Apetalous – without petals
Apex – distal end, tip – Opposite: base
Aphlebia – (Arecaceae) a narrow, strap-like, very spiny leaflet quite different in form from normal leaflets, found at the very base of the adult sessile leaves of, i.a., Eremospatha and Laccosperma
Apical – of the apex; distal
Apical placentation – the placenta is situated at the apex of the ovary
Apicidal capsule – dehiscing at the apex
Apicifixed anther – hanging, seemingly attached at the top
Apical meristem (intermediary or open) – minute meristem present in the growing tips of roots or buds
Apical placentation – one or several ovules developing at the apex (top) of the ovary
Apical septum – a septum in the upper part of the ovary, which originates by the bulging up of the locules such that the stylar canal traverses it
Apiculate – ending in an abrupt, short point
Apiculus – short, sharp, but not stiff point
Apocarpous – with free carpels, most noticeable in fruit – Opposite: syncarpous
Apocole – the elongated (usually subterranean and non-photosynthetic) part of the cotyledonary hyperphyll below the haustorium and above the cotyledonary sheath in monocotyledons
Apocolpium (of pollen grains) – an area at the pole of a zonocolpate pollen grain, which is delimited by lines connecting the apices of the colpi
Apotact aestivation – a form of cochlear aestivation, where the perianth part with its two margins outside those of the adjacent tepals are not immediately next to the one with the two margins inside
Apotracheal axial parenchyma – metatracheal axial parenchyma; axial parenchyma which is not associated with vessels
Apotracheal banded parenchyma – axial parenchyma consisting of bands two or more cells wide; narrow-banded (sensu Carlquist): bands two or three cells wide; wide-banded (sensu Carlquist): bands more than three cells wide
Apotropous ovule – an anatropous ovule with a ventral raphe (ovule curved abaxially)
Appendicular epigyny – the initially convex ovary becoming inferior by early vertical growth beneath the tepals making the entire apical meristem concave; initiation of the youngest floral primordia occurs on this concave meristem; the inferior ovary forms through congenital adnation of the carpels to the bases of the tepals and stamens; a central concavity develops in the convex top of the floral axis due to development of appendicular tissues
Appendiculate – with appendage or appendages
Appressed – lying close and flat (e.g. hairs on a stem)
Aquatic – living in water
Arachnoid (type of indument) – cobweblike, tangled cottony, the hairs in several directions and tangling
Arborescent – becoming tree-like
Arbuscular endomycorrhiza – vesicular mycorrhiza; a type of mycorrhiza with glomeromycetes, in which the fungus penetrates the cortical cells of the roots; the mycorrhiza forms highly branched characteristic structures, arbuscules or vesicles, exchanging water and nutrients; in the Arum type hyphae grow in the intercellular space, whereas in the Paris type hyphae grow between the cells
Arbutoid mycorrhiza – penetrating the outer cortical cells of the hair roots, although these are covered by a Hartig net, in which the hyphae grow along the cell walls or form an entire envelope
Archespore – one or several cells from which the megasporocyte or microsporocyte develops; the archespore may be unicellular or multicellular
Arcuate – curved like a bow
Areolate – with an areole or areolae, divided into distinct spaces by boundary lines
Areole (areola, pl. areolae) – areas on a surface divided from similar areas by a division line such as a vein; in Cactaceae: a modified axillary short shoot
Areolate tectum (of pollen grains) – with areoles present in the tectum
Aril – an appendage partially or completely enveloping the seed, sometimes resembling a third integument, and arising from the funicle (or the hilum?)
Arillar collar – (Annonaceae) fleshy organ around the hilum, an outgrowth of the seed coat
Arillate seed – provided with an aril
Arilloid (of seed appendages) – arillode; resembling an aril but non-funicular in origin
Arista – a long, bristle-like, pointed axis
Aristate apex – with a long, bristle-like point
Aristulate – bearing a small, sharp bristle
Armature – general term for the presence of spines, prickles etc
Arm cells (of leaves) – (Poaceae) chlorenchyma cells with cell wall invaginations
Armed – with sharp defensive structures
Aromatic – producing volatile oils with discernible odours (fragrance)
Article – a segment of a fruit constricted at intervals and breaking along these constrictions (in e.g. a lomentum)
Articulated – jointed
Ascending funicle, ovule, or stem – curved upwards, growing upward (sometimes indirectly)
Ascidiate carpel – tubular to pitcher-shaped, widening in upper part; the carpel primordium is initially U-shaped, and if the area between the arms of the U becomes meristematic (the meristematic cross-zone), the carpel develops as if it were a tube – Opposite: plicate carpel
Asepalous – without sepals
Asperous – rough
Asperulate – slightly rough with small hairs
Asperulous – slightly rough
Asterad embryogenesis – a three-tiered proembryo is formed with a vertical division in the apical cell and a transverse division in the basal cell; the apical cell may divide by an oblique wall and, at the time of formation of a quadrant, a wedge-shaped epiphysis initial is cut off which later gives rise to the epicotylary region; the remaining three cells of the quadrant produce the cotyledons; the middle cell of the proembryonic tetrad gives rise to the entire hypocotyledonary region
Asterosclereid, astrosclereid – a fairly short sclerenchyma cell (sclereid) that differs from a brachysclereid by its often conspicuously branched shape
Astringent taste – making the mouth pucker, bitter
Asymmetrical – with the two sides of the part or organ not equal – Opposite: symmetrical
Atactostele – a type of stele in which the vascular bundles are arranged irregularly within the parenchyma (ground tissue)
Atectate pollen grain – see Intectate
Atropous ovule – see Orthotropous ovule
Attenuate – gradually tapering over a long distance
Aulacospermous – individual endothelial cells in a seed protrude into the endosperm, the endosperm hence becoming alveolate
Auricle – ear-like lobe
Auricled – see Auriculate
Auriculate – equipped with ear-like structures, usually near the base
Autogamous – self-fertilizing, when ovules are fertilized by pollen grains from the same flower
Awl-shaped – gradually tapering to a sharp thin point
Awn – (Poales) a fine bristle ending an organ
Axial parenchyma – type of secondary xylem parenchyma, in which the parenchyma cells originate from fusiform cambial initials; the cells of the axial parenchyma may be as long as the fusiform initials from which they originated or, usually, much shorter due to transverse division prior to the differentiation
Axicorn – (Campanuloideae) tissue on the inside of the fruit, which by its drying perforates the pericarp and allows the seed being dispersed
Axil – the angle between the stem and the leaf
Axile – belonging to the axis
Axile placentation – the ovules are attached to the axis of the ovary, to the inner angle of the cells of a syncarpous ovary, in which the placentas are situated in separate locules; the ovules are attached along the sutures of the closed carpel, i.e. in the corner formed by the ventral areal of the carpel in an apocarpous or syncarpous gynoecium
Axillary – arising in an axil, the point between the stem and the leaf or another organ which arises from the stem
Axillocytic stomata – stoma in an axillary position attached to two lateral walls at the distal, marginopolar end of the single subsidiary cell
Axis – main line of development of a plant or organ; (of inflorescence) the main stem or branch part from which the flowers are produced; (of ovary) the central column or the central part where the inner angles of the cells meet