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• Diodia virginiana

Diodia virginiana — Virginia buttonweed

Facts

Virginia buttonweed is native to the eastern U.S., reaching the northern edge of its range just south of New England. It is a spreading, prostrate perennial that can show up as a weed in lawns and other disturbed areas of the south. However, it is listed as rare farther north in New Jersey and Indiana. Look for its distinctive, four-parted white flowers borne in the leaf axils along floppy, squarish stems. The opposite leaves are joined across the stem by a hairy tissue, and they sometimes are mottled yellow due to a virus. It has thick roots by which it can spread vegetatively. It resembles Diodia teres, but the latter is much more upright-growing, much hairier, and has narrower leaves.

Habitat

Anthropogenic (man-made or disturbed habitats)

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

  Calyx symmetry

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

  Carpels fused

  the carpels are fused to one another

  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 surface

  the filament is smooth, with no hairs or scales

  Flower description

  the flower has an inferior ovary, with or without a hypanthium

  Flower petal color

  • pink to red
  • white

  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 flower has two or more completely separate styles

  Fusion of sepals and petals

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

  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

  Nectar spur

  the flower has no nectar spurs

  Number of pistils

  1

  Number of sepals, petals or tepals

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

  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 hairs (Viola)

  NA

  Petal number

  4

  Petal tips (Cuscuta)

  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 appendages

  the sepals do not have appendages on them

  Sepal appendages (Oenothera)

  NA

  Stamen attachment

  the stamens are not attached to the petals or tepals

  Stamen number

  4

  Stamen position relative to petals

  the stamens are lined up with the petals

  Staminodes

  there are no staminodes on the flower

  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 ribs

  NA

  Fruit (pyxis) dehiscence

  NA

  Fruit features (Brassicaceae)

  NA

  Fruit length

  0.6–0.9 mm

  Fruit locules

  two

  Fruit type (general)

  the fruit is dry but does not split open when ripe

  Fruit type (specific)

  the fruit is a schizocarp (when dry it splits into sections, each holding one or more seeds)

  Legumes (Fabaceae)

  NA

  Mericarp segment shape (Desmodium)

  NA

  Other markings on berry

  NA

  Ovary stipe

  the ovary or fruit does not have a stipe

  Placenta arrangement

  the plant has axile placentation, in which the ovules are attached where the septa of a compound ovary are united, usually on the central axis, or to the septa themselves

  Rows of seeds in fruit (Brassicaceae)

  NA

  Septum in fruit (Brassicaceae)

  NA

  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

  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

  Spines on plant

  the plant has no spines

• 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

  Hairs on underside of leaf

  the underside of the leaf is fuzzy or hairy

  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 edges

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

  Leaf blade length

  20–32 mm

  Leaf blade shape

  • the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
  • the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)

  Leaf blade surface colors

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

  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 spines

  there are no spines on the leaf edges

  Leaf teeth and lobes

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

  Leaf type

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

  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 (lobed or unlobed but not separated into leaflets)

  Stipels

  NA

  Stipule features

  NA

  Stipules

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

• Place

  Habitat

  terrestrial

  New England state

  Connecticut

  Specific habitat

  man-made or disturbed habitats

• Stem, shoot, branch

  Branched tendrils

  NA

  Flowering stem cross-section

  the flowering stem is roughly square

  Hair between stem nodes

  the stem has hairs between the nodes

  Leaves on stem

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

  Plant height

  20–80 cm

  Tendril origin

  NA

  Tendrils

  the plant does not have tendrils

Wetland status

Usually occurs in wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae