Glossary - general

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Facial – used of one of the surfaces

Facies – general aspect of plant

Facultative (of life form or habitat requirement) – occasional or incidental, as opposed to obligatory or necessary – Opposite: obligate

Falcate – curved like a scythe or sickle

Farinaceous – mealy, resembling flour, the surface covered with small white particles

Farinose – covered with a meal-like powder

Fasciated – very flattened; in stems abnormally flattened and widened

Fascicle – a cluster of similar organs arising from more or less the same point (e.g. leaves or flowers)

Fascicled – in bundles; in close groups

Fasciclodes – sterile fascicles, as in stamens of some Calophyllaceae, Clusiaceae and Hypericaceae

Fascicular cambium – present within the vascular bundles

Fasciculate (of erect branches) – in close bundles

Fasciculate hairs – hairs present in bundles (fascicles)

Fastigiate branch – erect and parallel; ‘bundled’

Felted (of indumentum) – matted, with intertwined hairs; resembling felt

Female flower – flower with functional female parts but without (or with only rudimentary) male parts

Fenestration – with translucent areas like a window (i.a. leaves or petals)

Fenestrate pollen grain – lophate; with large window-like spaces without a tectum

Fibre – (1) elongated lignified cell of wood or bast other than vessel or parenchyma element; (2) wood element in general; a fairly long sclerenchyma cell, often with inconspicuous simple pits, usually being differentiated directly from meristematic cells; fibres occurring in the xylem are called xylary fibres

Fibre tracheid – a xylem fibre which is transitional between a tracheid and an extreme libriform fibre; a fibre tracheid resembles a tracheid in its possession of bordered pits, although these have only slightly raised borders in the fibre tracheid and usually are less conspicuous than those of tracheids; fibre tracheids provide mechanical strength

Fibrillate – with fibres; with a finely lined appearance

Fibrillose – with many fine fibres

Fibrous – composed of, or including, fibres

Fibrous endotegmen – containing a high amount of fibres

Fibro-vascular veins – mixed vessels and fibres

Fig – the compound inflorescence or fruit of species of Ficus; syconium

Filament – the stalk which bears the anthers, usually distinct from the connective

Filamentous – formed of thin fibres

Filiform – slender, thread-like

Filiform apparatus (of megagametophyte) – a complex of cell wall invaginations in synergids

Fimbriae – slender, hair-like processes

Fimbriate – of the margin, bordered by rather broad hair-like processes (as distinct from hairs or slender spines); fringed

Fimbriate stigma – fringed with long slender hair-like processes

Fimbriolate – bordered by very fine and very slender hairs or hair-like processes

Fischer’s rule (of pollen grains) – the apertures form in pairs at six points in the tetrahedral tetrad

Fissure – deep and narrow split

Fissured – cracked with deep splits, usually used of bark

Fissuring – splitting so as to cause deep longitudinal cracks

Fistular stem – cylindrical and hollow

Flabellate – fan-shaped

Flabellate venation – with several veins approximately equal in prominence diverging radially at the base and branching and running to the apex of the lamina

Flabelliform – fan-shaped

Flaccid – limp, drooping

Flagella – (Araceae) shoots with long slender internodes and reduced leaves

Flagellate – whip-like

Flagellum – (some species of Calamus) a sterile inflorescence modified as a climbing organ in the form of a barbed whip

Flaking off – exfoliating; coming off in flat, irregularly shaped pieces

Flange – ring-like projection on the outside or inside of a cylinder or rounded shape

Flat ptyxis – plane

Flexuous – sinuous, bent alternately in different directions

Floccose – covered with woolly hairs rubbing off easily

Flocculent – with small tufts of woolly hairs

Flocculose – like wool, with dense soft interwoven hairs

Floral – belonging to the flower(s)

Floral bract – (Cyperaceae) membranous scale-like structure in the spicoid-type inflorescence unit, each of which subtends a male flower comprising a single stamen only; the lowest two floral bracts usually have a keel and are opposite

Floral prophyll – see Bracteole

Floret – small flower; in Asteraceae, a single flower; in Poaceae, the flower plus its bracts (lemma and palea)

Floriferous – bearing flowers

Florigerous bract – subtending a flower (cluster)

Flower – an axis bearing one or more pistils (a pistillate flower) or one or more stamens (a staminate flower) or both (a perfect flower), and usually one or more whorls of perianth members (tepals)

Flowering eye – point of emergence from the stem of the inflorescence

Fluorescent wood – safranine-staining of xylem followed by blue light excitation is a method of differentiating lignin-rich and cellulose-rich cell walls; lignin-rich cell walls fluoresce red or orange, whereas cellulose-rich cell walls fluoresce green to yellow

Flush – emergent young leaves or flowers on trees and large shrubs, all coming out at the same time

Fluted (of stems, or of cylindrical objects) – with alternating longitudinal rounded ridges and grooves

Foetid – stinking

Foliaceous – leaf-like

Foliage – the leaves of plants

Foliar – belonging to the leaf (leaves)

Foliose – leafy

Follicle – a pod arising from a single carpel, opening along the inner (adaxial) suture to which the seeds are attached

Follicular – shaped like a long thin fruit opening by a single suture

Foot layer (of pollen grains) – the inner layer of the ectexine

Foramen (pl. foramina; of leaf teeth) – a narrow cavity, circular in cross-section

Foramen (pl. foramina; of pollen grains) – see Pore

Foraminate pollen grain – see Porate pollen grain

Foraminate phloem – see Interxylary phloem

Forate pollen grain – pantoporate; with pores all over the tectum

Forisome – (Fabaceae) P-protein body found in the cytoplasm of sieve tubes; forisomes are involved in plugging the pores of the sieve plate by changing shape, and are made up of contractile protein that is responsive to changes in Ca²⁺ concentration

Fork – branching point

Fornicate – with scale-like appendages

Fossaperturate pollen grain – an equatorially aperturate, lobate pollen grain with the apertures in the indentations between the lobes

Fothergilloid leaf tooth – similar to altingioid leaf tooth, but basically symmetrical and without glands, and the lateral veins on the abaxial side of the tooth are usually absent or very weak and short if present

Fovea – small pit

Foveolate – minutely pitted, with small depressions

Foveolate tectum (of pollen grains) – ornamentation consisting of rounded depressions (foveolae, lumina) more than 1 µm in diameter; the distance between foveolae is greater than their width

Free – neither adhering nor united; usually of floral parts

Free-central placentation – see Central placentation

Free nuclear division – mitotic division of nuclei without accompanying cytokineis, i.e. nuclei divide in a common cytoplasm, the cell walls only forming around each nucleus later

Free venation – no veins uniting to form a network

Fruit – the ripened ovary; the seed-bearing organ, with or without adnate parts

Frutescent – with the charactes of a shrub; becoming shrubby

Fruticose – with the characters of a shrub; shrubby

Fugaceous – falling off early

Functionally male – used when both female and male are present in the flower but only the male parts are functional

Funicle, funiculus – the stalk of the ovule and seed, attaching it to the placenta; seed stalk

Funicular – deriving from the funicle

Funnel-shaped, funnel-form – proximally tubular, abruptly widening to a wider distal part (infundibuliform)

Furcate – forked; with sharp terminal lobes

Furfuraceous – scurfy, with small soft scales

Furrowed bark – with longitudinal grooves or channels

Fused – completely united organs, whether connate or adnate

Fusiform – of a three-dimensional structure: straight, tapering from a wider middle towards both ends, spindle-shaped

Fusoid cells – somewhat fusiform, spindle-shaped