Wilson, L. M. and C. B. Randall. 2003. Biology and Biological Control of Knapweed. USDA-Forest Service FHTET-2001-07. 2nd Edition.
| achene |
A small, one-seeded fruit that does not split
at maturity |
| alternate |
Leaves that are arranged singly along a stem;
one leaf or bud at each node on alternate sides of the stem. |
| aspirator |
An apparatus used to suck insects into a
container. Can be as simple as in mouth aspirator, or mechanical as in a
gasoline- or battery-powered vacuum aspirator. |
| basal |
At the base of a plant or plant part. |
| biennial |
A plant which lives two years. |
| biological control |
The intentional use of control a weed’s
natural enemies for control purposes. Also referred to as biocontrol. |
| bolting |
Plant stage at which the flower stalk begins
to grow. |
| bract |
A small, leaf-like structure below a flower. |
| capitulum (pl. caputula) |
Seedhead of plants in the sunflower family. |
| coordinate |
Any of a set of numbers used to specify a
point on a line or in a plot |
| cotyledon |
First leaf-like structures that appear after
germination; seed leaves. |
| density |
Number of individuals per unit area. |
| dissemination |
Dispersal. Can be applied to seeds or
insects. |
| elytron (pl. elytra) |
Hardened front wing of a beetle. |
| emergence |
Act of adult insect leaving the pupal exoskeleton, or from winter or
summer dormancy. |
| exoskeleton |
External skeleton of the body of an insect. |
| floret |
One of the small, closely clustered flowers
forming the head of a composite flower in the sunflower family. |
| frass |
Plant fragments, usually mixed with
excrement, deposited by feeding insects. |
| gall |
An abnormal growth on a plant, usually
induced by an insect that lives within the gall. |
| grub |
A soft, thick-bodied, C-shaped beetle larva. |
| head |
A group of flowers borne tightly together. |
| host specificity |
The highly-evolved, often obligatory
association between an insect and its host (i.e., weed). |
| inflorescence |
The flowering part of a plant. |
| instar |
The phase of an insect’s development between
molts. |
| involucre |
A circle of bracts under an inflorescence. |
| larva (pl. larvae) |
Immature insect stage between the egg and
pupa. |
| lobed |
A leaf with shallow or deep, rounded
segments, as in a knapweed rosette leaf. |
| metabolic sink |
Site of the plant that receives photosynthate (food) produced by the
plant, diverting the resource from the plant’s normal use. |
| metamorphosis |
A change in body form during insect
development (e.g., change from caterpillar to moth). |
| molting |
Process of insect development that involves
shedding its exoskeleton and producing an exoskeleton for the next instar. |
| mottled |
Surface having colored spots or blotches. |
| organdy |
A fine transparent cloth. |
| oviposit |
To lay or deposit eggs. |
| ovary |
The part of the flower that contains the
ovules or seeds. |
| pappus |
A tuft of hairs, scales orbristles at the tip of an achene in flowers of
the sunflower family. |
| perennial |
A plant that lives more than two years. |
| pheromone |
A substance given off by an insect used to
communicate with other insects of the same species. |
| proleg |
A fleshy, unsegmented, abdominal walking appendage of some insect
larvae, common among caterpillars. |
| pubescence |
Hairs covering a leaf, stem, or flower. |
| pupa (pl. pupae) (v. pupate) |
Non-feeding, inactive stage between larvae
and adult in insects. |
| puparium |
The hardened, thickened skin of a mature
larva within which the pupa and adult are formed. |
| quadrat |
A specific area used to sample vegetation
(e.g., 1 square meter). |
| qualitative |
Measurement of descriptive elements (e.g.,
age class, distribution). |
| quantitative |
Measurement of quantity - number or amount
(e.g., seeds per capitula). |
| receptacle |
Part of the stem to which the flower is
attached. |
| rosette |
A compact, circular, normally basal cluster
of leaves. |
| senescence |
Final stage in a plant’s lifecycle. |
| snout |
‘Nose’ of a weevil. The elongate head of a
weevil with mouth parts at the tip (apex). |
| spine |
A stiff, pointed plant part. |
| synchrony |
Occurring at the same time (e.g., plant
flowering and insect oviposition). |
| thorax |
Body region of an insect behind the head and
abdomen, bearing the legs and wings. |
| transect |
A straight line of varying length along which
plants are periodically sampled individually or in quadrants. |
| univoltine |
Produce only one generation per year. |
| variable |
A quantity that can have more than one of a
set of values (e.g., plant height). |
| weevil |
A type of plant-eating beetle; the adult has
a snout, and the larva is a C-shaped grub (aka snout beetle). |
| x-axis |
Horizontal axis or line in a coordinate
system. |
| y-axis |
Vertical axis or line in a coordinate system. |
