Glossary of Botanical Terms

Data taken from the Flora of Australia Glossary, Ferns, Gymnosperms and Allied Groups

abaxial of the side or surface of an organ, facing away from the axis, e.g. the lower or dorsal surface of the lamina. cf. adaxial
acaulescent lacking an aerial stem or trunk. cf. caulescent
acicular stiff and needle-like
acrophyll an adult lamina on the high-climbing portions of some ferns in Lomariopsis and related genera. cf. bathyphyll
acroscopic pointing towards the apex. cf. basiscopic
acrostichoid with sporangia densely covering the abaxial surface of the lamina, as in Acrostichum
acuminate gradually tapering to a protracted point
acute terminating in a distinct but not protracted point, the converging edges separated by an angle less than 90°
adaxial of the side or surface of an organ, facing towards the axis, e.g. the upper or ventral surface of the lamina. cf. abaxial
adnate fused to an organ of a different kind
aerophore a localised outgrowth associated with ventilation, as in Cyathea
alate winged
alete used of a spore which forms alone, i.e. not in diads or tetrads, and hence lacks the laesura characteristic of monolete and trilete spores
amphistomatic bearing stomata on both upper and lower lamina surfaces. cf. hypostomatic
anadromous a type of venation in which the first set of veins in each segment of the frond originates from the acroscopic side of the midrib, as in Polystichum australiense. cf. catadromous
anastomosing of veins, forming a network or reticulum
anisophyllous having leaves unequal in size and shape at any one point along a branch. cf. isophyllous
anisotomous dichotomies resulting in unequal branching. cf. isotomous
anisovalvate when the two valves of a sporangium are unequal in size. cf. isovalvate
annular arranged in or forming a ring
annulus the elastic ring of cells in a sporangium that initiates dehiscence
antheridium the fertile organ of a male gametophyte or the male organ of a bisexual gametophyte, in which the male gametes are formed. pl. antheridia
antrorse bent, and pointing towards the apex. cf. retrorse
apiculus a small abrupt flexible point at the apex of a pinna or pinnule. adj. apiculate
apogamous applied to pteridophytes in which a sporophyte develops from gametophyte cells, other than a fertilised egg
apogamy the state of being apogamous
apomict a plant that produces viable spores without fertilisation
appressed pressed closely against a surface (or another organ) but not united with it
arachnoid composed of fine tangled hairs like a cobweb
arborescent resembling a tree in height
archegonium the structure that produces the female gamete or egg. pl. archegonia
areole a space enclosed by the veins of a reticulum
aristate having a stiff bristle-like tip
articulate jointed; having joints where separation may occur naturally
asperous rough to the touch
attenuate of pinnae, with sides narrowed concavely to the apex or to the base
auricle an ear-like lobe at the base of a lamina, pinna or pinnule. adj. auriculate
baculate of a spore, having pillar-like processes, always longer than broad and higher than 1 µm
basiscopic pointing towards the base. cf. acroscopic
bathyphyll a basal lamina in some high-climbing ferns in Lomariopsis and related genera. cf. acrophyll
bisculptate of spores, with two different elements in the ornamentation, which cover the entire surface, as in the spores of some species of Pyrrosia
bordered pit a pit (q.v.) in which the margin projects over the thin closing membrane, as in coniferous wood
brachyblast a short lateral branch
bristle a stiff hair which is more than one cell broad at the base
bulbiferous bearing bulbils
bulbil a small bud formed on the lamina; a mode of vegetative reproduction
bullate having a blistered or puckered surface
caducous shed easily
capitate of hairs, having a rounded apical cell
cartilaginous hard and tough, resembling cartilage
catadromous a type of venation in which the first set of veins in each segment of the frond develops from the basiscopic side of the midrib, as in Lastreopsis marginans and L. tenera. cf. anadromous
catenate united or linked as in a chain
cauda a narrow tail-like appendage. adj. caudate
caudex a thick erect stock or trunk, especially of tree ferns
caulescent developing an aerial stem or trunk. cf. acaulescent
cell the basic unit of plant structure consisting, at least when young, of a protoplast surrounded by a wall
chartaceous thin and papery
chlorophyll pigment(s) constituting the green colouring matter of plants and absorbing radiant energy in photosynthesis. adj. chlorophyllous
ciliate fringed with hairs
circinnate (=circinate) coiled in a spiral with the tip innermost
clathrate latticed or pierced with apertures like a trellis
clavate club-shaped
coenosori fused sori
columella the axis of a cone or cone-like fruit, e.g. in Diselma
commissure a juncture or seam; in Pellaea, a continuous marginal sorus formed when laterally expanded fertile vein endings coalesce
compound of a leaf, having the blade divided into two or more distinct leaflets
concolorous coloured uniformly; the same colour on both sides. cf. discolorous
conduplicate folded flat together lengthwise; of developing leaves
cone a group of sporophylls arranged compactly on a central axis
conform similar in shape to an earlier mentioned organ (e.g. in Thelypteridaceae, conform terminal pinna are shaped like lateral pinnae)
cordate of a leaf blade, broad and notched at the base; heart-shaped (in two dimensions)
coriaceous leathery
corm in Isoetes, the condensed stem, which may be 2–5-lobed
costa the midrib of a pinna
costule the midrib of a pinnule or segment of lower order, except the central vein of an ultimate segment which is usually termed the midrib
crenate with small, rounded teeth; scalloped
crenulate minutely scalloped
cristate in ferns, having a tasselled margin to the fronds
cryptocotular mode of germination in which cotyledons remain enclosed within the seed
Ctenitis-hairs articulated hairs with dark red septae, as in Ctenitis, Lastreopsis and allied genera (Dryopteridaceae)
cuneate wedge-shaped, e.g. base of a pinna
cupular cup-shaped
cyathiform cup-like
cymbiform boat-shaped; describing pollen with a single linear pore
deciduous shed seasonally
decrescent gradually decreasing in size, e.g. lower pinnae of Christella species
decurrent extending downwards beyond the point of insertion, e.g. of a lamina extending downwards to form a flange along the rachis
decussate borne in pairs alternately at right angles to each other
deflexed bent abruptly downwards
deltoid triangular with the sides of about equal length
dentate of margins, toothed
denticulate finely toothed
dichotomous divided into two approximately equal branches resulting from the division of a growing point
dictyostele a stele (q.v.) with large overlapping leaf gaps
dimidiate halved, as when half of an organ is so much smaller than the other half that it seems absent. In Adiantum, applied to pinnules in which the basiscopic lamina is reduced. The pinnule therefore appears ±rectangular or trapeziform rather than flabellate
dimorphic having two different forms, especially of fronds. cf. monomorphic
dioecious having the male and female reproductive structures on separate plants. cf. monoecious
diploid having two of the basic sets of chromosomes in the nucleus. cf. haploid, polyploid
discolorous of different colours; of leaves, having the two surfaces different in colour; variegated. cf. concolorous
distal remote from the point of origin or attachment. cf. proximal
dorsal of a lateral organ, facing away from the axis
dorsifixed attached by or at the back
dorsiventral having structurally different upper and lower surfaces
echinate of a spore, spiny
eglandular without glands
elaters in Equisetum, appendages of the spore which help in dispersal
eligulate lacking a ligule
emarginate having a broad shallow apical notch
ensiform sword-shaped
entire having a smooth margin, not dissected or toothed
epidermis the outermost layer of cells of an organ, usually only one cell thick. adj. epidermal
epimatium expanded fleshy seed-bearing bract scale in certain conifers, especially some Podocarpaceae
epiphyte a plant growing on (but not parasitic on) another plant
erose of a margin, finely and irregularly eroded or incised
eusporangiate having sporangia with walls more than one cell thick. cf. leptosporangiate
excurrent having the vein extend beyond the apex of a segment as a mucro (q.v.)
exindusiate lacking an indusium
exine outer layer of a spore wall (or second layer, if perine is present). cf. perine
falcate sickle-shaped
false veins rows of thickened cells in a leaf/leaflet which are not part of the vascular system, as in some genera of the Hymenophyllaceae
fastigiate with extensive lateral branching and no clear single leading branch
fenestrate pierced with small window-like openings
ferruginous rust-coloured
fimbriate of a margin, fringed with fine hairs
flabellate fan-shaped
floccose covered with soft tangled woolly hairs
Florin ring a distinct raised ring around stomatal openings of Podocarpus, formed by raised subsidiary cells that are differentiated from other epidermal cells
frond the whole leaf of a fern or cycad, including the lamina and the stipe or petiole
fugacious shed or withering away very early
fuscous dusky
gametophyte a plant or generation that bears gametes during the sexual life cycle
gemmiferous bearing asexual buds or bulbils
glabrescent becoming glabrous
glabrous without hairs or scales
gland a structure with a secretory function, embedded or projecting from the surface of the plant
glandular having glands or functioning as a gland
glaucous dull green with a bluish white or white lustre
globose almost spherical
gymnosperm a seed plant with the ovules borne on the surface of a sporophyll
haploid with one set of chromosomes in the nucleus. cf. diploid, polyploid
hastate spear-shaped; of a leaf blade, narrow and pointed but with two basal lobes spreading approximately at right angles
helicoid branching repeatedly on the same side. In Adiantum, applied to anadromous fronds in which basal basiscopic pinnae are well-developed (i.e. pinnate), but corresponding acroscopic pinnae are reduced to simple pinnules. The stipe thus appears to branch dichotomously into two helically curved rachises, with pinnate pinnae apparently arising from their upper sides
hemisaprophyte a plant which obtains its nutriment partly from dead organic matter and partly from photosynthesis
herbaceous soft in texture; midway in thickness between membranous and coriaceous, usually applied to the lamina
heteroblastic with two or more distinct kinds of shoot. cf. homoblastic
heterophyllous having leaves that are not uniform along a branch, e.g. in Huperzia, with long leaves in the lower portions and smaller reduced leaves distally. cf. homophyllous
heterosporous producing two kinds of spores (male and female, or microspores and megaspores). cf. homosporous
hirsute bearing coarse rough relatively long hairs. cf. villous
hispid clothed with short stiff hairs or bristles
holosaprophyte a plant which obtains its nutriment entirely from dead organic matter
homoblastic with one kind of shoot. cf. heteroblastic
homophyllous with all leaves uniform along a branch. cf. heterophyllous
homosporous producing only one type of spore from which develops a gametophyte producing both male and female gametes. cf. heterosporous
hyaline translucent, almost like clear glass
hydathode water- or mineral-excreting pores at the ends of some veins, e.g. in Grammitidaceae and some Davalliaceae
hypostomatic bearing stomata on one leaf surface only, usually the lower or abaxial surface. cf. amphistomatic
incised cut deeply, sharply and often irregularly (an intermediate condition between toothed and lobed)
incurved bent or curved inwards or upwards; of leaf margins, curved towards the adaxial surface
indumentum the epidermal appendages, e.g. hairs or scales, collectively
indurated hardened
indusiate bearing an indusium
indusium the covering of a sorus, either a specialised organ or the incurved margin of the lamina
internal hairs in leaves of Isoetes, projections into the lacunae
involucre the indusium of members of the Hymenophyllaceae
isophyllous leaves equal in size and shape at any point on the branch. cf. anisophyllous
isotomous having all dichotomies resulting in equally thin branches. cf. anisotomous
isovalvate having the two valves of a sporangium equal in size. cf. anisovalvate
labium an outgrowth above the sporangium which partially or wholly covers the ligule
lacuna of Isoetes, a cavity within the leaves. pl. lacunae
laesura a ridge which surrounds the apertural slit (through which the gemetophyte germinates) in spores of Polypodiophyta; the shape of this ridge reflects the type of spore alignment in the tetrad. pl. laesurae
lamina the ‘blade’ of a frond
lanuginose woolly
leaf gap a point in the stele at which the vascular supply to a leaf is attached
leptosporangiate having sporangia with the walls only one cell thick. cf. eusporangiate
ligulate bearing a ligule; strap-shaped
ligule a membranous structure towards the base of the upper leaf surface in Isoetes and Selaginella
lithophytic growing on rock
lunate crescent-shaped
manoxylic having secondary wood of a loose texture with discontinuous xylem and a large proportion of included parenchyma
marcescent withering without falling off
massula group of microspores enclosed in a hardened mucilage. pl. massulae
medullated protostele a protostele in which the xylem has a core of non-vascular tissue
megasporangium the larger of the two kinds of sporangia produced in the sexual life cycle of a heterosporous plant. Produces megaspores
megaspore the larger of the two kinds of spores produced in the sexual life cycle of a heterosporous plant, giving rise to the female gametophyte. They may be monomorphic as in Selaginella, or polymorphic as in some Isoetes species. cf. microspore
megasporocarp a sporocarp containing megasporangia
megasporophyll a specialised leaf upon which (or in the axil of which) one or more megasporangia are borne
meristele the portion of a stele received by each leaf
mesophyll photosynthetic tissue of a green leaf
microsporangium the smaller of the two kinds of sporangia produced in the sexual life cycle of a heterosporous plant
microspore the smaller of the two kinds of spores produced in the sexual life cycle of a heterosporous plant, giving rise to the male gametophyte. cf. megaspore
microsporocarp a sporocarp containing microsporangia
midrib the central, and usually the most prominent, vein of a leaf or leaf-like organ
monoecious having the male and female reproductive parts in separate organs but on the same plant. cf. dioecious
monolete of a spore, bilateral, having a single straight scar
monomorphic of uniform shape and size. cf. dimorphic
monosulcate a type of spore with a single germination pore or furrow
mucro a sharp abrupt terminal point. adj. mucronate
mucronulate having a very small mucro; diminutive of mucronate
muri low ridges
muricate covered with short hard-pointed outgrowths
nest fronds specialised shield-like basal fronds in some ferns (e.g. Platycerium) which accumulate leaf litter
nodosity in Adiantum, a callus or swollen node, often lacking normal colouration, where a pinna or pinnule stalk arises from a rachis
ob- a prefix signifying the opposite of
obconical cone-shaped but attached at the narrower end
obtuse blunt or rounded at the apex, the converging edges separated by an angle greater than 90°
orthostichous arranged in regular vertical rows on a stem or axis
orthotropic mode of growth of vertical branches or leading shoots, especially in conifers where lateral (plagiotropic) branches may have different morphology
pachycaul thick-stemmed, sparingly branched and succulent, with a massive parenchymatous pith and cortex and relatively little secondary wood
paleate clothed with scales
palmate of a leaf, divided into several leaflets which arise at the same point. cf. palmatifid, pinnatifid
palmatifid of a leaf, deeply (but not completely) divided into several lobes which arise (almost) at the same level. cf. palmate, pinnatifid
papilla a small elongated protuberance on the surface of an organ, usually an extension of one epidermal cell. adj. papillose
paraphysis sterile filaments occurring among the sporangia of some ferns. pl. paraphyses
parenchyma plant tissue consisting of mature living cells that are relatively unspecialised in function
pectinate comb-like
pedate of a palmate or palmately-lobed leaf, having the lateral segments divided again
pedicel the stalk of a sporangium
peduncle the stalk of a sporocarp, e.g. in Marsilea
peltate having the stalk attached to the lower surface usually at or near the centre; umbrella-shaped
perine an outer (perisporial) spore wall, present in some families and genera of ferns. cf. exine
peripheral fibre strands multicellular fibre strands which strengthen the periphery of the leaf in some Isoetes species
perispore the folded membrane of most spores, forming an ornamental external covering
persistent remaining attached to the plant beyond the expected time of falling
phanerocotular mode of germination where cotyledons emerge from the seed and above ground
phyllopodium an outgrowth from the stem to which a stipe is articulated
pilose hairy, the hairs soft and clearly separated but not sparse
pinna a primary segment of the lamina in a compound leaf. pl. pinnae
pinnate of a lamina, divided into pinnae, with the pinnae (leaflets) arising at points along the rachis
pinnatifid cut deeply (but not to midrib) into lobes that are spaced out along the axis. cf. palmate, palmatifid
pinnatisect pinnately dissected down to the midrib but having the segments confluent with it
pinnule a leaflet, i.e. ultimate segments of the lamina
pit of a cell wall, a small hollow or depression
plagiotropic mode of growth of lateral branches, growing horizontally away from the leading shoot and maintaining a different morphology, especially in conifers
platyspermic describing flat and bilaterally symmetrical seeds
pluricellular having many cells, as in some hairs
polymorphic having more than two distinct morphological variants
polyploid having more than two of the basic sets of chromosomes in the nucleus. cf. diploid, haploid
proliferous having adventitious leaf buds which produce new plants
prothallus the gametophyte of a fern or fern ally
protostele a simple primitive type of stele having a solid central vascular core
proximal near to the point or origin of attachment. cf. distal
pseudo- false; apparent but not genuine
ptyxis pattern of folding and rolling shown during leaf development
pubescent clothed with short soft erect hairs
punctate marked with dots, depressions or translucent glands
pustule a blister-like prominence, often in which a sorus occurs. adj. pustulate
pyriform pear-shaped
quadrate squarish
rachis a midrib of the lamina, or of a primary, secondary, tertiary etc. pinna. When unqualified, refers to the midrib of the frond, i.e. the main axis above the lowermost primary pinna. Also spelled rhachis. pl. rachises
radial applied to a rootstock in which the fronds radiate and the roots are borne on all sides of the organ
radiospermic describing radially symmetrical seeds
ray of woody stems, a radial band of cells traversing the conducting elements
receptacle of ferns, the axis bearing the sporangia and sometimes also paraphyses
recurved curved or curled downwards or backwards
reflexed bent sharply downwards or backwards
reniform kidney-shaped
reticulum a network, e.g. of veins. adj. reticulate
retrorse bent, and pointing away from the apex. cf. antrorse
rhizoid a thread-like unicellular absorbing structure occurring, in the vascular plants, in gametophytes of ferns and some related plants
rhizome the creeping (often underground) or climbing stem of a fern
rhizophore in Selaginella, a leafless stem that produces roots
rhomboidal diamond-shaped or almost so
rootstock a swollen root together with the whole or a portion of a very short stem
rugose deeply wrinkled
rugulose covered with minute wrinkles
saccate with pouched projections
saprophyte an organism living on dead organic matter and usually lacking chlorophyll
sarcotesta the fleshy outer layer of the seed coat in cycads
scaberulous slightly or minutely rough to the touch
scabrate rough
scale a thin flap of tissue of epidermal origin; a thin scarious trichome which is flattened and variously shaped
scandent climbing
septate divided internally by septa
septum a partition. pl. septa
sericeous clothed with silky hairs
serrate toothed, like a saw blade
sessile lacking a stalk
seta a stiff hair or bristle. pl. setae
setiferous producing or having setae
setose covered with bristles
simple undivided; of a frond, not divided into leaflets; of a hair or an inflorescence, not branched
sinus membrane the membrane of a depression between adjacent lobes in a pinna, especially in the Thelypteridaceae
sobol a shoot originating near the ground
solenostele (=siphonostele) a tubular stele with both external and internal phloem
soral flap the specialised fertile lobe unique to Adiantum
sorus a cluster of sporangia. pl. sori
spathulate spoon-shaped; broad at the tip and narrowed towards the base
spinulose with small spines
sporangiate bearing spores
sporangiophore the stalk of a sporangium
sporangium a structure within which spores are formed. pl. sporangia
spore a unicellular or few-celled sexual or asexual reproductive propagule
sporocarp a fruiting body containing sporangia
sporophyll a specialised leaf-like organ that bears one or more sporangia
sporophyte a plant or phase that bears the spores formed during the sexual reproductive cycle
squamule a small scale
squarrose with spreading and divergent scales or processes
stele the vascular system of rhizome or stem, together with leaf traces
stellate star-shaped
stipe the stalk of the frond; that portion of the midrib of the frond between the rhizome and the lowermost primary pinna
stomium the region of a sporangium at which dehiscence occurs and the spores are released
stramineous straw-coloured, pale yellow
strigose with stiff sharp slanting hairs, hair-like scales or bristles
strobilus a cone-like body, as in the Lycopodiaceae and Selaginellaceae, consisting of sporophylls borne close together on the axis. pl. strobili
subulate narrow and tapering gradually to a fine point
sulcate grooved; furrowed
superficial when applied to sori, those arising from the surface, rather than the margin, of a lamina, pinna or pinnule
synangium structure formed by the fusion of sporangia, e.g. in Psilotum, Marattia. pl. synangia
terete circular or almost so in cross section
ternate in groups of three
testiculate testicle-like
tetrad a group of four
tetrahedral having four sides
tetraploid having four of the basis sets of chromosomes in a nucleus
tetrastichous arranged in four regular vertical rows, but not necessarily decussate
tomentum a hairy covering of short closely matted hairs. adj. tomentose
tracheid an elongated closed cell of wood having secondary thickening and conducting water
trans-lacunar diaphragm a plate two or three cells in thickness, perforated by pores, in the leaves of Isoetes
trichome an epidermal outgrowth, e.g. a hair (branched or unbranched), a papilla
trilete of spores, with a three-pronged scar
trimerous arranged in whorls of three
triploid having three of the basic sets of chromosomes in the nucleus
triquetrous triangular in cross section and acutely angled
truncate with an abruptly transverse end, as if cut off
tubercle a small wart-like outgrowth
tuberculate covered with tubercles
urceolate urn-shaped
vascular bundle the primary fluid-conducting system of a plant
vein a strand of vascular tissue
velum a membranous flap-like envelope which partially or wholly covers the sporangium
venation the arrangement of the veins in a lamina
vermiculate with worm-like projections
vernation the arrangement of the unexpanded fronds in a bud
verrucose covered with wart-like outgrowths, warted
villous clothed with long weak hairs. cf. hirsute
xylem the tissue, in a vascular plant, that conducts water and mineral salts from the roots to the leaves
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