Glossary - general

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Habit – general appearance (e.g. erect or sprawling, herbaceous or woody)

Halophyte – plant adapted to saline soils; plants with seeds having the ability to germinate in salt water

Half epigyny – in perigynous flowers the perianth parts and the androecium are situated around the ovary, the ovary thus being semi-inferior (cf. Hypogyny and Epigyny)

Hamulus – (Orchidaceae) a hook-shaped recurved apical part of the rostellum

Hapaxanthic – with a single flowering period, dying after flowering and fruiting

Haploid – with a single set of chromosomes (unpaired)

Haplostemonous androecium – with the stamens in one whorl, as many as the petals or the sepals and opposite to the outer perianth whorl

Haplostemony – see Haplostemonous androecium

Hapter – adhesive usually unicellular hair, which is attached to the substrate and secretes viscous polysaccharides

Hartig net – the network formed by fungal hyphae which weave between the epidermal cells of the root in ectomycorrhizal symbiotic associations

Hastate – when a leaf base has two more or less triangular lobes diverging from the petiole apex

Hastula – (Arecaceae) a small flange of tissue found at the junction of the lamina with the petiole in most palmate and costapalmate leaves on the abaxial and/or adaxial face

Haustorial – pertaining to the haustorium

Haustorium (pl. haustoria) – the sucker of a parasitic plant, by which it anchors itself into the host plant

Haustorium (of ovule) – an absorbtive structure at the end of the cotyledonary hyperphyll usually enclosed by the seed and occurring in the embryo or seedling of monocots

Head – capitulum; short, dense inflorescence

Heartwood – the innermost and oldest, dead, wood in a tree, usually distinct in colour and properties from the outer sapwood

Helical – coiled like a spring

Helically twisting – spiralling in three dimensions

Helicocytic stomata – with an additional ring of subsidiary cells outside the anisocytic configuration; with a helix of four or more subsidiary cells surrounding the guard cells

Helicoid – spiralling in three dimensions

Helicoid cyme – inflorescence with the flowers appearing alternately to the right and left of the coiled sympodial axis; a monochasia cymose inflorescence, repeatedly branching on the same side of the pedicel (plants probably with paired lateral bracteoles), thus forming a spiral when viewed from above

Helm-like, helmet-like – shaped like a helmet, i.e. hollow and vaulted (i.a. petals in some Orchidaceae)

Helobial endosperm – a cell wall is laid down between the first two nuclei, one half subsequently developing endosperm according to the cellular pattern and the other half according to the nuclear pattern

Hemiamphitropous ovule – half amphitropous

Hemianatropous ovule – half anatropous, the ovule axis at 90o to the stalk

Hemicampylotropous ovule – half campylotropous

Hemi-epiphytic – plant that first roots in soil, then climbs up other plants and develops aerial roots

Hemiorthotropous ovule – half orthotropous

Hemiparacytic stomata – stoma accompanied by a single subsidiary cell which is parallel to the longitudinal axis of the pore, and longer or shorter than the guard cells

Hemiparasite – a parasitic plant which is capable of some photosynthesis, yet receives a portion of its nutrients and water from their host plant

Hemispherical – in the shape of half a sphere or globe

Herb – plant without persistent woody stem above ground

Herbaceous – 1) an annual herb or one with annual stems from a perennial root; 2) with the texture of a herb, soft and pliable

Hermaphrodite – bisexual, with stamens and pistil in the same flower

Hesperidium (pl. hesperidia) – (Citreae) a fruit with a tough leathery rind and with the fleshy pulpy interior composed of carpels, which are filled with juicy vesicles that in reality are specialized hair cells; the exocarp becomes a thick spongy layer, whereas the endocarp becomes juicy

Heterobifacial leaf – with different upper and lower surfaces; the normal condition – Opposite: isobifacial leaf

Heteroblastic – of different development, e.g., of pseudobulbs in Graphorchis, with only one internode elongated, the remaining basal ones very short

Heterocarpy – with fruits of more than one kind, i.a., in Asteraceae where the achenes of ray florets may have a different shape from those of disc florets

Heterocellular wood rays – parenchymatic wood ray cells of several different sizes

Heterochlamydous – with the perianth divided into a distinct calyx and a distinct corolla

Heterocolpate pollen grain – with both simple and compound colpi

Heterogamous – with two kinds of flowers; e.g. in Asteraceae with heads of central, usually hermaphroditic disc flowers and marginal unisexual or neuter ray flowers

Heterogeneous – not uniform, of several kinds

Heterogeneous wood rays – see Heterocellular wood rays

Heteromorphic, heteromorphous – (1) with variation in normal structure; (2) with organs differing in length, e.g. long/short styles

Heterophyllous – with leaves of different kinds on one plant – Opposite: homophyllous

Heteropolar pollen grain – the proximal and distal faces of the exine are different (in ornamentation, shape, or apertures)

Heterostylous species – with flowers of two or more types, having styles of different lengths and anthers on different levels – Opposite: homostylous

Hexacolpate pollen grain – with six colpi

Hexacytic stomata – stoma accompanied by six subsidiary cells comprising two lateral pairs, that are parallel to the long axis of the pore, and two terminal cells; the second lateral pair have the same length as the stomatal complex or the pair of polar cells are as wide as the stomatal complex

Hexagonal – six-angled

Hexalobate – with six lobes

Hexarugate pollen grain – with six colpi

Hexarugorate pollen grain – hexacolporate; with six compound apertures with pores in furrows

Hexatomosulcate pollen grain – with a six-armed sulcus

Hilar – pertaining to the hilum

Hilum (of seed) – the scar left on the seed from its point of attachment

Hippocrepiform – see Hippocrepomorphic

Hippocrepomorphic – horseshoe-shaped, i.e. shaped like the letter “U” with the ends curved inwards

Hirsute – with rather coarse, stiff hairs

Hirtellous – softly or minutely hirsute or hairy

Hispid – with stiff hairs or bristles; more sharply bristly than hirsute

Hispidulous – minutely hispid

Hoary – covered with a thin white pubescence resembling frost

Hollow style – with a mucilaginous central canal, through which the pollen tube grows prior to fertilization

Holoparasite – a non-photosynthetic plant without chlorophyll, hence entirely dependent on their host plant for the supply of nutrients and water

Homocellular wood rays – parenchymatous wood ray cells with approximately the same size

Homogamous – with all flowers of the same kind

Homogeneous – uniform, of one kind – Opposite: heterogeneous

Homogeneous wood rays – see Homocellular wood rays

Homophyllous plant or species – with leaves of one kind – Opposite: heterophyllous

Homostylous – a species with flowers with styles (and usually stamens) uniformly positioned – Opposite: heterostylous

Hood – three-dimensional shape with the sides and apex curved inwards

Hooded – forming a hood, a three-dimensional shape with the sides and apex curved inwards

Hook – a slender process with a curved or bent part at the tip

Horned – with a horn, a tapering three-dimensional structure resembling an elongated cone, often curved

Horseshoe-shaped – see Hippocrepomorphic

Hyaline – almost transparent

Hydathode – water gland, an organ which extrudes water or non-sweet fluid

Hydrogamous flower – with pollination effected by water

Hydrophytic – adapted to permanently flooded or waterlogged conditions

Hydropote – (Nymphaeales) gland-like cell complex on the abaxial surface of the lamina, responsible for the uptake of nutrients and water and/or the secretion of mucilage

Hygrochastic capsule – dehiscing only when moistened (due to harmomegathic changes) and then releasing seeds (closing again when dried)

Hygrophilous – moisture-loving, growing in wet or damp sites

Hygrophyte – growing in wet or waterlogged soil

Hygroscopic hairs – hairs that react to the presence or absence of water by movement, or by turning slimy

Hypanthium – cup-shaped extension of the floral axis (i.e. the receptacle), enlargement of the basal part of the flower, seemingly bearing calyx, corolla, stamens and surrounding the ovary; believed formed out of fused bases of calyx, corolla and stamens; sometimes imprecisely called ‘floral tube’

Hyperparasite – a parasite the host of which is also a parasite (in, e.g., some Loranthaceae and Santalaceae)

Hyperphyll – the terete unifacial apical part of a cotyledon of an embryo or a seedling of a monocotyledon

Hyperstigma – appendage above the stigma; mucilage is secreted at or just inside the narrow pore at the apex of a flower made up of separate carpels and with an urceolate floral cup and reduced perianth; epidermal cells are modified as a sort of transmission/guiding tissue; pollen grains which germinate there proceed to any of the individual carpels

Hyphodromous venation – with a single primary vein and all other venation absent, rudimentary or concealed within a coriaceous or fleshy lamina

Hypochile (of a flower) – (Orchidaceae) the basal (proximal) part of the labellum, which is divided into two or three distinct parts or lobes

Hypocotyl (of seed or seedling) – that part of the main axis below the junction of the cotyledons, but above the radical; usually more developed among monocotyledons

Hypocotyledonary tuber – a tuber developed from the hypocotyl

Hypocrateriform – bowl-shaped

Hypodermal – pertaining to the hypodermis

Hypodermal cell (of trichoblast) – present in the hypodermis

Hypodermal endothecium – present in the hypodermis of a microsporangium (pollen sac)

Hypodermis – protecting and supporting cell layer present beneath the epidermis of a stem/branch; hypodermis consists of layers of collenchyma cells or sclerenchyma cells (the latter is frequent among monocotyledons)

Hypog(a)eous – present beneath the earth’s surface

Hypogeal germination – germinating beneath the earth’s surface; cotyledons remaining underground during germination (as in Fabaceae); in hypogeal seedlings the epicotyl is elongated – Opposite: epigeal germination

Hypogyny – the sepals, petals and stamens inserted on the receptacle below and free from the ovary, the ovary thus being superior

Hypophyll – the bifacial basal part of the cotyledon of a monocotyledon, its margins joining adaxially at the base of the hyperphyll

Hypophysis – the terminal cell of the suspensor of the proembryo; the hypophysis forms part of the radicula

Hypopodial tuber – developing from the hypopodium, the elongated first internode below the prophylls (present particularly in axillary shoots with sylleptic growth, i.e. development of axillary buds from primordium without resting period)

Hypostasis – with core and annulus; a group of lignified cells in the chalazal end of the megagametophyte

Hypotropous ovule – the micropyle points proximally; the raphe is either dorsal (abaxial) or ventral (adaxial)

Hysteranthous – produced after the flowers