Urtica urens — burning nettle

Characteristics

• Clonal plantlets

  Bulbils

  the plant does not appear to have bulbils

  Bulblets replace flowers

  there are no bulblets where the flowers are located

• Flowers

  Anther attachment

  the anther is attached by its base to the filament

  Anther color

  the anthers show no hint of a pink, reddish or purplish tint

  Anther opening

  the anthers have narrow slits or furrows that run lengthwise along the anthers

  Anther spurs

  the anthers do not have spurs on them

  Anther tube length

  0 mm

  Calyx growth after flowering

  the calyx grows to cover or partially cover the fruit

  Calyx symmetry

  there are two or more ways to evenly divide the calyx (the calyx is radially symmetrical)

  Carpels fused

  • NA
  • the carpel is solitary or (if 2 or more) the carpels are not fused to one another

  Cilia on petals

  NA

  Cleistogamous flowers

  there are no cleistogamous flowers on the plan

  Corolla morphology

  NA

  Corolla palate

  NA

  Corona lobe length

  0 mm

  Epicalyx

  the flower does not have an epicalyx

  Epicalyx number of parts

  0

  Filament surface

  • NA
  • the filament is smooth, with no hairs or scales

  Flower description

  the flower has a superior ovary, and lacks a hypanthium

  Flower orientation

  the flower points upwards or is angled outwards

  Flower petal color

  NA

  Flower reproductive parts

  the flower has either only pollen- or only seed-producing parts

  Flower symmetry

  there are two or more ways to evenly divide the flower (the flower is radially symmetrical)

  Flowers sunken into stem

  no

  Form of style

  NA

  Fringed petal edges

  NA

  Fused stamen clusters

  NA

  Fusion of sepals and petals

  both the petals and sepals are separate and not fused

  Horns in hoods (Asclepias)

  NA

  Hypanthium

  the flower does not have a hypanthium

  Hypanthium length

  0 mm

  Inflorescence length

  5–25 mm

  Inflorescence one-sided

  the flowers are arrayed in a spiral around the inflorescence axis or branches, or occur singly, or in several ranks

  Inner tepals (Rumex)

  NA

  Length of flower stalk

  At least 0 mm

  Marks on petals

  NA

  Nectar spur

  the flower has no nectar spurs

  Number of branches in umbel

  0

  Number of carpels

  1

  Number of pistils

  1

  Number of sepals, petals or tepals

  there are four petals, sepals, or tepals in the flower

  Number of styles

  0

  Ovary position

  the ovary is above the point of petal and/or sepal attachment

  Perianth shape

  • the perianth is cupuliform (cup-shaped)
  • the perianth is rotate (platter-shaped, the corolla flattened, circular, with nearly horizontally spreading lobes)

  Petal and sepal arrangement

  the flower includes only one cycle of petals or sepals

  Petal and sepal colors

  green to brown

  Petal appearance

  NA

  Petal base

  NA

  Petal folding in bud

  NA

  Petal folds or pleats

  NA

  Petal glandular dots or scales

  NA

  Petal hairs (Viola)

  NA

  Petal hairs on inner/upper surface

  NA

  Petal length

  0 mm

  Petal length relative to sepals

  NA

  Petal nectaries

  NA

  Petal number

  0

  Petal shape

  NA

  Petal tip shape

  NA

  Petal tips (Cuscuta)

  NA

  Petal width

  0 mm

  Raceme attachment (Veronica)

  NA

  Reproductive system

  each flower has only carpels or only stamens, but both types of flower are present on each plant (monoecious)

  Scales inside corolla

  NA

  Sepal and petal color

  NA

  Sepal appearance

  the sepals are green or brown, and leaf-like in texture

  Sepal appendages

  the sepals do not have appendages on them

  Sepal appendages (Oenothera)

  NA

  Sepal auricles

  the sepals have no auricles

  Sepal cilia

  • the sepals do not have cilia
  • the sepals have cilia on their edges

  Sepal color

  green to brown

  Sepal features

  one or more sepals have a spine at the tip

  Sepal length

  0.5–0.9 mm

  Sepal number

  4

  Sepal orientation

  • the sepals are pressed against the corolla, or jutting stiffly upward
  • the sepals are slightly curved outwards from the corolla

  Sepal relative length

  NA

  Sepal shape

  • the sepal outline is eliiptic (widest near the middle and tapering at both ends)
  • the sepal outline is ovate (widest below the middle and broadly tapering at both ends)

  Sepal texture

  the sepals are either very thin but flexible, like a membrane, or they are leaf-like in texture

  Sepal tip shape

  the sepal tip is obtuse (is bluntly pointed)

  Sepal uniformity

  • all the sepals are about the same size
  • one or more of the sepals is much narrower or shorter than the others

  Sepals fused only to sepals

  the sepals are separate from one another

  Spur length

  0 mm

  Spur number

  NA

  Stamen appendages

  stamen appendages are absent

  Stamen attachment

  the stamens are not attached to the petals or tepals

  Stamen lengths differ

  the stamens are all approximately the same length

  Stamen morphology

  the stamens within each cycle are the same

  Stamen number

  4

  Stamen position relative to petals

  the stamens are lined up with the sepals

  Stamen relative length

  anything

  Stamens fused

  the stamens are not attached to one another

  Staminodes

  there are no staminodes on the flower

  Stigma position

  the stigmas are in another position

  Style length

  0 mm

  Style relative length

  NA

  Umbel flower reproductive parts

  NA

  Upper lip of bilabiate corolla

  NA

• Fruits or seeds

  Achene relative orientation

  the achenes are perpendicular to the plane of the perianth (vertical)

  Achene shape

  the achenes are oval in outline

  Achene surface (Polygonum)

  NA

  Achene type

  the fruit is an achene (dry, indehiscent, and usually one-seeded)

  Berry color

  NA

  Capsule color (Viola)

  NA

  Capsule ribs

  NA

  Capsule splitting

  NA

  Fruit (pyxis) dehiscence

  NA

  Fruit cross-section

  the fruit is at least somewhat flattened

  Fruit features (Brassicaceae)

  NA

  Fruit length

  1.5–1.8 mm

  Fruit length relative to sepals

  the fruit is shorter than its associated sepals

  Fruit locules

  one

  Fruit shape

  the fruit is another shape than those described

  Fruit stalk orientation

  the fruits point upward or spread or curve outward

  Fruit type (general)

  the fruit is dry but does not split open when ripe

  Fruit type (specific)

  the fruit is an achene (dry, usually one-seeded, does not separate or split open at maturity)

  Fruit width

  1.1–1.3 mm

  Hair type on fruit

  the hairs on the fruits are simple (not branched), don’t have glands, and are not woolly

  Hairs on fruit

  the fruits have hairs on them

  Legumes (Fabaceae)

  NA

  Mericarp length

  0 mm

  Mericarp segment shape (Desmodium)

  NA

  Other markings on berry

  NA

  Ovary stipe

  the ovary or fruit does not have a stipe

  Ovary stipe length

  0 mm

  Placenta arrangement

  the plant has basal placentation, where one or a few ovules develop at the base of a simple or compound ovary

  Rows of seeds in fruit (Brassicaceae)

  NA

  Schizocarpic fruit compression

  NA

  Schizocarpic fruit segments

  0

  Seed number

  1

  Seed relative length

  the seed is longer than it is wide

  Seed surface

  the seed is covered with short, round or cylindrical projections (papillae)

  Seeds comose

  no hairs

  Septum in fruit (Brassicaceae)

  NA

  Wings on fruit

  the fruit does not have wings on it

  prickles on fruits

  the fruits do not have thorn-like defensive structures

• Glands or sap

  Glands on leaf blade

  the leaf blades do not have glandular dots or scales

  Sap

  the sap is clear and watery

  Sap color

  the sap is clear

• Growth form

  Growth form

  the plant is an herb (it has self-supporting stems)

  Horizontal rooting stem

  the plant does not have stolons

  Lifespan

  the plant lives only a single year or less

  Parasitism

  the plant is not parasitic

  Plant color

  the leaves or young stems of the plant are green

  Plants darken when dry

  no

  Spines on plant

  • the plant has no spines
  • there are spines on the plant

  Underground organs

  there is a thickened taproot on the plant

• Leaves

  Bracteole number (Apiaceae)

  0

  Bracts in plantain (Plantago)

  NA

  Final leaf segment length (compound lvs only)

  0 mm

  Final leaf segment length to width ratio (compound lvs only)

  0

  Final leaf segment width (compound lvs only)

  0 mm

  Floral bracts

  the flower has one or more bracts associated with it

  Hairs on leaf stalk

  the petiole has hairs on it

  Hairs on underside of leaf

  the underside of the leaf is fuzzy or hairy

  Hairs on upper side of leaf

  the upper side of the leaf is fuzzy or hairy

  Hooked hairs on underside of leaf

  no

  Inflated hairs on leaf

  the leaf blade does not have inflated hairs on it

  Leaf arrangement

  opposite: there are two leaves per node along the stem

  Leaf blade base

  the leaf has a distinct leaf stalk (petiole)

  Leaf blade base shape

  the base of the leaf blade is cuneate (wedge-shaped, tapers to the base with relatively straight, converging edges), or narrow

  Leaf blade base symmetry

  the leaf blade base is symmetrical

  Leaf blade bloom

  the underside of the leaf has no noticeable bloom

  Leaf blade edges

  • the edge of the leaf blade has lobes, or it has both teeth and lobes
  • the edge of the leaf blade has teeth

  Leaf blade flatness

  the leaf is flat (planar) at the edges

  Leaf blade hairs

  the leaf blade has simple hairs with no glands, and not tangled or wooly

  Leaf blade length

  18–90 mm

  Leaf blade primary vein pattern

  the secondary veins branch off at intervals from the primary vein

  Leaf blade shape

  the leaf blade is elliptic (widest near the middle and tapering at both ends)

  Leaf blade surface colors

  the upper side of the leaf blade is relatively uniform in color

  Leaf blade texture

  the leaf blade is herbaceous (has a leafy texture)

  Leaf blade vein pattern

  the major veins form a net-like pattern due to splitting and rejoining

  Leaf blade veins

  • the leaf blade has one main vein running from the base towards the tip (it may or may not have secondary veins)
  • the leaf blade has three or more main veins that start at or near the leaf blade base and run from the base towards the tip (it may or may not have secondary veins)

  Leaf blade width

  12–45 mm

  Leaf duration

  the leaves drop off in winter (or they whither but persist on the plant)

  Leaf form

  the leaves are green, with an expanded blade and a leaf-like texture

  Leaf hair orientation

  the hairs are standing up straight or curved in different directions

  Leaf sheath length

  0 mm

  Leaf shiny

  the upper side of the leaf is dull or slightly shiny

  Leaf spines

  there are no spines on the leaf edges

  Leaf stalk

  the leaves have leaf stalks

  Leaf stalk attachment to leaf

  the petiole attaches at the basal margin of the leaf blade

  Leaf stalk base

  the petiole base is narrow where it attaches to the stem

  Leaf stalk length

  10–25 mm

  Leaf teeth and lobes

  the leaf blade margin has forward-pointing teeth

  Leaf tip

  the tip of the leaf blade is acute (sharply pointed)

  Leaf type

  the leaves are simple (i.e., lobed or unlobed but not separated into leaflets)

  Leaf types

  There is a gradual change in appearance of the leaves from the base (or near the base) of the plant to those from further up on the stem, with leaves progressively changing as one moves higher on the stem (often becoming shorter, or less toothed/lobed, and/or with shorter petioles).

  Leaf variation

  the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem

  Leaflet number

  0

  Leaflet petiolules

  NA

  Leaves per node

  there are two leaves per node along the stem

  Pinnately compound leaf type

  NA

  Specific leaf type

  the leaves are simple (i.e., lobed or unlobed but not separated into leaflets)

  Stipels

  NA

  Stipule features

  NA

  Stipule fused to leaf stalk

  the stipules are not fused to the petioles

  Stipule length

  1–3 mm

  Stipule shape

  the stipules are triangular

  Stipules

  the plant has stipules

  Teeth per side of leaf blade

  6–11

• Place

  Habitat

  terrestrial

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont

  Specific habitat

  • man-made or disturbed habitats
  • meadows or fields

• Scent

  Plant odor

  the plant does not have much of a smell

• Stem, shoot, branch

  Branched tendrils

  NA

  Direction of stem hairs

  the hairs point mostly upwards to outwards

  Flowering stem cross-section

  the flowering stem is roughly square

  Hair between stem nodes

  the stem has hairs between the nodes

  Hairs between stem nodes

  the hairs on the stem are plain, without glands or branches, and not tangled

  Hooked hairs on stem between nodes

  no

  Leaves on stem

  there is at least one full leaf above the base of the flowering stem

  Length of hairs between stem nodes

  10–70 mm

  Plant height

  10–80 cm

  Stem bloom

  there is no powdery or waxy film on the stem

  Stem hair distribution

  the hairs on the stem are distributed more of less uniformly

  Stem nodes swollen

  the stem is not swollen at the nodes

  Stem orientation

  the stems are upright or angled outwards

  Stem roughness between nodes

  the stem does not feel rough

  Stem spacing

  the plant is solitary, or a few plants are growing together

  Stem succulence

  the stems are not succulent

  Tendril origin

  NA

  Tendrils

  the plant does not have tendrils

  Wings on stem

  the stem does not have wings on it

Wetland status

Not classified

In New England

From Flora Novae Angliae dichotomous key