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Glossary of plant parts (X returns to directory)

achene

small single seeded fruit that does not split (strawberry "seed") X

adventitious

roots or stems arising from unexpected locations

androecium

all of the stamens in a flower

anther

pollen-containing part of stamen, equivalent to microsporangium in a flower

axillary

in the axil, or in the angle between petiole and stem

berry

fleshy fruit with one or more seeds in the pulp, not enclosed in hard shell (grape)

bipinnate

pinnately divided leaf in which the leaflets are again pinnately divided (honey locust)

bract

a leaf-like structure with one or many flowers in its axil, often smaller than regular leaves and otherwise modified (scaly, brown or different shape)

bulb

underground structure with swollen leaf bases enclosing a bud

calyx

all of the sepals, often green and when present the outermost whorl of flower parts

capitulum

head of flowers attached directly to a flat disc or common receptacle (daisy family)

capsule

a dry fruit containing many seeds and opening by many pores or slits (poppy)

carpel

one section of an ovary, corresponding to a single sporophyll X

catkin

an inflorescence of many single-sex flowers without petals

chamaephyte

low growing plant with living structures visible all year round

cladode

stem structure more or less resembling a leaf, but in the axil of a reduced leaf (Asparagus fern has them)

compound leaf

divided into two or more leaflets (opposite of simple)

cordate

heart-shaped

corm

compressed underground stem, often enclosed in scale leaves

corolla

all of the petals, often colored, the next whorl in from the calyx in a complete flower

corona

tubular outgrowth usually from the petals (daffodil)

corymb

inflorescence in which pedicels branch at different points from the peduncle but flowers form a flat top

cotyledon

first seedling leaf or leaves

cyme

determinate inflorescence; ends with flower that opens first and later flowers arise as branches from the side

decussate

opposite leaves arranged so that each pair is at right angles to the one below X

dehiscence

opening or splitting of a fruit or anther

determinate

pattern of growth in which stem cannot continue growth, usually because it is terminated by a flower

dichotomous

branching into two equal structures (stems, veins etc.) leading to a"Y"

dioecious

male and female flowers on different plants

distichous

(usually alternate) leaves arranged in parallel rows along each side of stem

divided

leaf blade not entire but not compound (many oaks)

drupe

fleshy usually with one or few seeds enclosed in hardened inner wall of ovary (peach)

endosperm

storage tissue other than cotyledons in many seeds, formed by fertilization of central cell

entire

simple leaf with smooth margins, not compound or divided (elm)

epicotyl

the stem of a seedling or embryo between the cotyledons and the first true leaf

epigeal/geous

pattern of germination in which cotyledons remain below ground

epigynous

other floral structures attached above ovary, which is therefore inferior X

epiphyte

plant that grows on another plant

filament

stalk of stamen carrying anther

follicle

dry, many seeded fruit that splits along one side (milkweed)

fruit

mature ripened ovary of an angiosperm, usually developing after pollination of an ovary and containing seeds

geophyte

plant that overwinters by dying back to underground structure

glabrous

without hairs

glaucous

having a white waxy bloom

gynoecium

all of the pistils in a flower

helophyte

aquatic plant rooting at the bottom

hemicryptophyte

plant that overwinters by dying back to crown of buds at soil surface

hirsute

hairy all over

hydrophyte

free-floating water plant

hypocotyl

the part of an embryo or seedling between the radicle and the cotyledons X

hypogeal/geous

pattern of germination in which cotyledons remain below ground

hypogynous

other floral structures attached below the ovary, which is therefore superior

indehiscent

fruit that remains closed at maturity

indeterminate

growth pattern in which stem continues growth indefinitely

indusium

scaly covering over fern sporangia

internode

stem between nodes

involucre

overlapping bracts around an inflorescence

lamina

blade of leaf

leaflet

separate part of lamina of compound leaf

legume

dry, single chambered, multiseeded fruit dehiscing along two edges (beans and peas)

lenticel

pore in outer bark of woody plants

ligule

membranous outgrowth at junction of lamina and leaf sheath in many grasses X

linear

leaf at least 10 times as long as broad with parallel margins

locule

chamber containing seeds in an ovary

megaphyll

generally a large leaf with veins that are internally connected to the vascular system of the stem

microphyll

small leaf, without veins

monoecious

having separate male and female flowers on the same plant

monopodial

when growth continues through single apical meristem (which may periodically form dormant terminal buds)

nectary

nectar secreting gland in a flower, or on stem or leaf

node

part of stem where one or more leaves are attached

nut

hard, indehiscent, single-seeded fruit (filbert)

nutlet

small , single-seeded portion of ovary typical of Lamiaceae

palmate

compound leaf in which all leaflets attached at same point
also pattern of veins radiating from the junction of the petiole and the lamina X

panicle

much-branched inflorescence

pappus

fine hairs replacing calyx in many asteraceae

pedicel

stalk of individual flower in an inflorescence

peduncle

stalk of inflorescence or of solitary flower

perianth

colective term for calyx and corolla

pericarp

ovary wall that becomes variously modified in fruits

perigynous

other floral structures attached to extension of the receptacle which partially encloses ovary

petal

single segment of the coralla

petiole

the stalk of a leaf, attaching the lamina to the node

phanerophyte

tall-growing plant with living structures visible all year

phyllotaxis

pattern of leaf arrangement on the stem; count from one leaf around the stem until meet another directly above; number of leaves/number of turns around stem X

pinnate

compound leaf with leaflets arrange along sides of common stalk
also pattern of veins which branch from along a single mid-rib

pistil

collective term for ovary, style and stigma; the innermost structure in a complete flower

pome

fleshy fruit formed from the enlarged receptacle of a perigynous flower (apple)

pubescent

covered in soft, fine hairs

raceme

indeterminate inflorescence; individual flowers attached by pedicels along a common stalk

rachis

portion of pinnate leaf to which leaflets are attached

radicle

first (embryonic) root of seedling

rhizome

horizontal underground stem

sagittate

arrow-head shaped

samara

dry, winged, indehiscent fruit (ash)

scape

leafless peduncle arising from a basal rosette of leaves (dandelion) X

schizocarp

fruit that splits into single seeded portions

sepal

single segment of calyx, often green, but may be colored

sessile

not stalked (leaves and flowers)

silicle/silicula

flat dry fruit about as broad as long, splitting around edges to reveal seeds on papery central septum

silique

dry fruit longer than broad, splitting on two edges to reveal seeds on papery central septum

simple

leaves with a continuous lamina (opp. of compound)

sorus

cluster of sporangia on a fern leaf

spadix

a fleshy spike of numerous small flowers (typical of Araceae)

spathe

green, colored or dry sheath enclosing inflorescence (typical of Araceae)

spike

indeterminate inflorescence in which sessile flowers arise along a common stalk X

spikelet

small spike enclosed by bracts forming part of the inflorescence of many grasses and sedges

spine

sharp, needle-like modification of a leaf

sporophyll

modified leaf bearing sporangia

stamen

pollen bearing structures between corolla and pistil in complete flower

staminode

sterile stamens in some flowers

stigma

surface at end of style where pollination occurs

stipules

pair of outgrowths at base of petiole in some plants

strobilus

terminal cluster of sporophylls or cone

style

region of pistil between ovary and stigma, sometimes elongated

sympodial

when growth continues through a series of axillary branches that seem to form a single stem

tendril

part of stem, leaf or petiole that can coil around supporting structures X

tepal

a name given to a perianth segment when the distinction between sepals and petals does not seem to apply (e.g. when they are all colored)

testa

outer covering of a seed

thallus

plant body that is not differentiated into root, stem or leaf

tomentose

covered in short hairs

thorn

pointed modification of a stem

trichome

hair-like outgrowth

trifoliate/trifoliolate

compound leaf with three leaflets

tuber

underground stem or root

umbel

inflorescence in which all pedicels arise from the same point at the top of the peduncle

undulate

wavy (leaf) margins

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