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• Gentianaceae
• Bartonia
• Bartonia iodandra

Bartonia iodandra — purple screwstem

Facts

Purple screwstem is a rare northeastern endemic found only in New England and eastern Canada. It inhabits swamps, peatlands, meadows and abandoned borrow pits. It is very similar in appearance to the much more common twining screwstem (Bartonia paniculata).

Habitat

Anthropogenic (man-made or disturbed habitats), bogs, fens (calcium-rich wetlands), meadows and fields, swamps

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 color

  there is a noticeable pink, reddish or purplish tint to the anthers

  Anther length

  0.4–1 mm

  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

  Calyx symmetry

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

  Carpel hairs

  the carpels have no hairs

  Carpels fused

  the carpels are fused to one another

  Cilia on petals

  • the petal margins do not have cilia
  • the petal margins have cilia

  Cleistogamous flowers

  there are no cleistogamous flowers on the plan

  Corolla palate

  no

  Corona lobe length

  0 mm

  Epicalyx

  the flower does not have an epicalyx

  Epicalyx number of parts

  0

  Filament length

  0.5–1 mm

  Filament surface

  the filament is smooth, with no hairs or scales

  Flower description

  the flower has a superior ovary, and lacks a hypanthium

  Flower diameter

  0.8–2 mm

  Flower length

  3–6.2 mm

  Flower orientation

  the flower points upwards or is angled outwards

  Flower petal color

  • pink to red
  • white

  Flower reproductive parts

  the flower has both pollen- and 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

  the style is lobed at the tip, and unbranched

  Fused stamen clusters

  NA

  Fusion of sepals and petals

  the petals or the sepals are fused into a cup or tube

  Hairs on flower stalk

  the flower stalk has no hairs on it

  Hairs on inflorescence

  the axis of the inflorescence has no hairs on it

  Horns in hoods (Asclepias)

  NA

  Hypanthium

  the flower does not have a hypanthium

  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

  Interior flower disk

  NA

  Marks on petals

  there are no noticeable marks on the petals

  Nectar spur

  the flower has no nectar spurs

  Number of carpels

  2

  Number of sepals, petals or tepals

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

  Number of styles

  1

  Ovary position

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

  Perianth shape

  the perianth is campanulate (bell-shaped, with a tube about as long as wide, flaring at the mouth)

  Petal and sepal arrangement

  the flower includes two cycles of petal- or sepal-like structures

  Petal and sepal colors

  • pink to red
  • white

  Petal appearance

  the petals are thin and delicate, and pigmented (colored other than green or brown)

  Petal folding in bud

  the petals in bud are arranged in a cycle with edges overlapping like roof shingles (imbricate)

  Petal folds or pleats

  the petals of the flower do not have folds or plaits

  Petal glandular dots or scales

  no

  Petal hairs (Viola)

  NA

  Petal length

  3–6.2 mm

  Petal length relative to sepals

  the petals are about equal in length to the sepals

  Petal number

  4

  Petal shape

  • the petal outline is lanceolate (lance-shaped; narrow, gradually tapering from the base to the tip)
  • the petal outline is oblong (rectangular, but with rounded ends)

  Petal tip shape

  the petal tip is acute (sharply pointed)

  Petal tips (Cuscuta)

  NA

  Petal width

  0.8–2 mm

  Raceme attachment (Veronica)

  NA

  Reproductive system

  all the flowers have both carpels and stamens (synoecious)

  Scales inside corolla

  no

  Sepal and petal color

  the sepals are different from the petals

  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

  • blue to purple
  • green to brown

  Sepal features

  one or more winged

  Sepal length

  1.5–3.2 mm

  Sepal number

  4

  Sepal orientation

  the sepals are pressed against the corolla, or jutting stiffly upward

  Sepal relative length

  the sepal lobes are longer than the fused portion

  Sepal shape

  • the sepal outline is lanceolate (lance-shaped; narrow, gradually tapering from the base to the tip)
  • the sepal outline is subulate (narrowly tapering from the base to the apex; awl-shaped)

  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 acuminate (tapers to a very narrow point)
  • the sepal tip is acute (is sharply pointed)

  Sepal uniformity

  all the sepals are about the same size

  Sepals fused only to sepals

  the sepals are fused to each other (not other flower parts), at least near their bases

  Spur length

  0 mm

  Spur number

  NA

  Stamen appendages

  stamen appendages are absent

  Stamen attachment

  the stamens are attached at or near the bases of the petals or tepals

  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 length

  0.8–1.5 mm

  Stigma position

  the stigmas are positioned in lines on the ovary

  Style petal-like

  the styles are not petal-like

  Style relative length

  the stigma does not protrude beyond the mouth of the corolla

  Umbel flower reproductive parts

  NA

  Upper lip of bilabiate corolla

  NA

• Fruits or seeds

  Achene relative orientation

  NA

  Achene shape

  NA

  Achene surface (Polygonum)

  NA

  Achene type

  NA

  Berry color

  NA

  Capsule color (Viola)

  NA

  Capsule splitting

  the capsule splits by two main valves, teeth or pores

  Fruit (pyxis) dehiscence

  NA

  Fruit cross-section

  the fruit is round in cross-section

  Fruit features (Brassicaceae)

  NA

  Fruit length

  4–6 mm

  Fruit length relative to sepals

  the fruit is longer than its associated sepals

  Fruit locules

  one

  Fruit shape

  the fruit is ovoid (egg-shaped)

  Fruit stalk orientation

  the fruits point upward or spread or curve outward

  Fruit type (general)

  the fruit is dry and splits open when ripe

  Fruit type (specific)

  the fruit is a capsule (splits along two or more seams, apical teeth or pores when dry, to release two or more seeds)

  Legumes (Fabaceae)

  NA

  Mericarp length

  0 mm

  Mericarp segment shape (Desmodium)

  NA

  Other markings on berry

  NA

  Placenta arrangement

  the plant has parietal placentation, where ovules develop on the wall or slight outgrowths of the wall forming broken partitions within a compound ovary

  Rows of seeds in fruit (Brassicaceae)

  NA

  Schizocarpic fruit compression

  NA

  Schizocarpic fruit segments

  0

  Seed length

  0.15–0.1 mm

  Seed relative length

  the seed is about as long as it is wide

  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)

  Lifespan

  • the plant lives for two years
  • the plant lives only a single year or less

  Parasitism

  the plant is a parasite of fungi (mycoheterotrophic)

  Plant color

  the plant lacks green pigments, even on the leaves or young stems

  Plants darken when dry

  no

  Spines on plant

  the plant has no spines

• Leaves

  Bracteole edges

  NA

  Bracteole length

  0 mm

  Bracteole number (Apiaceae)

  0

  Bracteole shape

  NA

  Bracteoles

  there are no bracteoles on the plant

  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 bract texture

  NA

  Floral bracts

  the flower does not have bracts

  Flower bract length

  0 mm

  Hairs on leaf stalk

  NA

  Hairs on underside of leaf

  the underside of the leaf is not hairy, or it has very few hairs

  Hairs on upper side of leaf

  the upper side of the leaf is not hairy, or it has very few hairs

  Hooked hairs on underside of leaf

  no

  Leaf arrangement

  alternate: there is one leaf per node along the stem

  Leaf blade bloom

  NA

  Leaf blade edges

  the edge of the leaf blade is entire (has no teeth or lobes)

  Leaf blade flatness

  NA

  Leaf blade hairs

  NA

  Leaf blade length

  0.5–4.5 mm

  Leaf blade primary vein pattern

  the secondary veins branch off at intervals from the primary vein

  Leaf blade shape

  the leaf blade is subulate (awl-shaped; narrowly tapering from the base to the tip)

  Leaf blade surface colors

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

  Leaf blade vein pattern

  NA

  Leaf duration

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

  Leaf form

  the leaves are small and thin and lack leaf stalks

  Leaf hair orientation

  NA

  Leaf spines

  there are no spines on the leaf edges

  Leaf stalk

  the leaves have no leaf stalks, but attach directly to the stem

  Leaf stalk attachment to leaf

  NA

  Leaf stalk base

  NA

  Leaf teeth and lobes

  the edge of the leaf blade is entire (has no teeth or lobes)

  Leaf tip

  the tip of the leaf blade is acuminate (tapers to a long, thin point)

  Leaf tufts in axils

  there are no clusters of smaller leaves growing out of axils

  Leaf type

  the leaves are simple (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 is one leaf per node along the stem

  Pinnately compound leaf type

  NA

  Specific leaf type

  the leaves are simple (lobed or unlobed but not separated into leaflets)

  Stipels

  NA

  Stipule edges

  NA

  Stipule features

  NA

  Stipule fused to leaf stalk

  NA

  Stipule length

  0 mm

  Stipule shape

  NA

  Stipules

  there are no stipules on the plant

  Teeth per side of leaf blade

  0

• Place

  Habitat

  • terrestrial
  • wetlands

  Specific habitat

  • bogs
  • fens (calcium-rich wetlands)
  • man-made or disturbed habitats
  • meadows or fields
  • swamps

• Scent

  Plant odor

  the plant does not have much of a smell

• Stem, shoot, branch

  Branched tendrils

  NA

  Direction of stem hairs

  NA

  Flowering stem cross-section

  • the flowering stem has strong or sharp angles, but is not square
  • the flowering stem is circular, or with lots of small angles so that it is roughly circular

  Hair between stem nodes

  the stem has no hairs between the nodes

  Hairs between stem nodes

  NA

  Hooked hairs on stem between nodes

  no

  Leaves on stem

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

  Plant height

  3–25 cm

  Stem hair distribution

  NA

  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

Occurs only in wetlands. (Wetland indicator code: OBL)

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae