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Native Plant Trust: Go Botany Discover thousands of New England plants

Crocanthemum bicknellii — hoary frostweed

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Facts

Hoary frostweed shares beneficial root fungi (ectomycorrhizae) with some oak species, so that oak seedlings benefit from establishing near a patch of hoary frostweed.

Habitat

Anthropogenic (man-made or disturbed habitats), grassland, meadows and fields, sandplains and barrens, woodlands

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
terrestrial
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Flower petal color
  • NA
  • yellow
Leaf type
the leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
Leaf arrangement
alternate: there is one leaf per node along the stem
Leaf blade edges
the edge of the leaf blade is entire (has no teeth or lobes)
Flower symmetry
there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
Number of sepals, petals or tepals
there are five petals, sepals, or tepals in the flower
Fusion of sepals and petals
both the petals and sepals are separate and not fused
Stamen number
  • 10
  • 11
  • 12
  • 13 or more
Fruit type (general)
the fruit is dry and splits open when ripe
Fruit length
3.5–5 mm
Show all 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 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)
    • there is only one way to evenly divide the calyx (the calyx is bilaterally symmetrical)
    Carpels fused
    the carpels are fused to one another
    Cleistogamous flowers
    the plant has some cleistogamous flower
    Corolla morphology
    NA
    Corolla palate
    no
    Corona lobe length
    0 mm
    Epicalyx
    the flower does not have an epicalyx
    Epicalyx number of parts
    0
    Flower appearance
    the flowers appear after the leaves have appeared
    Flower description
    the flower has a superior ovary, and lacks a hypanthium
    Flower number
    2–20
    Flower petal color
    • NA
    • yellow
    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 knob-like at the tip, and unbranched
    Fused stamen clusters
    NA
    Fusion of sepals and petals
    both the petals and sepals are separate and not fused
    Hairs on flower stalk
    the flower stalk has hairs on it
    Hairs on inflorescence
    the axis of the inflorescence has hairs entirely without glands
    Horns in hoods (Asclepias)
    NA
    Hypanthium
    the flower does not have a hypanthium
    Hypanthium length
    0 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
    5–10 mm
    Marks on petals
    there are no noticeable marks on the petals
    Nectar spur
    the flower has no nectar spurs
    Number of branches in umbel
    0
    Number of carpels
    1–10
    Number of pistils
    1
    Number of sepals, petals or tepals
    there are five 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
    Petal and sepal arrangement
    the flower includes two cycles of petal- or sepal-like structures
    Petal and sepal colors
    • green to brown
    • yellow
    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 rolled like an umbrella, each petal having one edge tucked inside and the other edge exposed (convolute)
    Petal folds or pleats
    the petals of the flower do not have folds or plaits
    Petal hairs (Viola)
    NA
    Petal length
    8–15 mm
    Petal length relative to sepals
    the petals are longer than the sepals
    Petal number
    5
    Petal tips (Cuscuta)
    NA
    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 appendages
    the sepals do not have appendages on them
    Sepal appendages (Oenothera)
    NA
    Sepal color
    • blue to purple
    • green to brown
    • pink to red
    Sepal length
    4–6 mm
    Sepal number
    5
    Sepal uniformity
    one or more of the sepals is much narrower or shorter than the others
    Stamen attachment
    the stamens are not attached to the petals or tepals
    Stamen lengths differ
    the stamens are didynamous (two long stamens and two short ones)
    Stamen number
    • 10
    • 11
    • 12
    • 13 or more
    Stamens fused
    the stamens are not attached to one another
    Staminodes
    there are no staminodes on the flower
    Style length
    Up to 1 mm
    Style petal-like
    the styles are not petal-like
    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
    the capsule has no prominent ribs or wings
    Capsule splitting
    the capsule splits by three main valves, teeth or pores
    Carpel beak length
    0 mm
    Fruit (pyxis) dehiscence
    NA
    Fruit cross-section
    the fruit is round in cross-section
    Fruit features (Brassicaceae)
    NA
    Fruit length
    3.5–5 mm
    Fruit length relative to sepals
    the fruit is shorter than its associated sepals
    Fruit locules
    three
    Fruit shape
    the fruit is ovoid (egg-shaped)
    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)
    Hair type on fruit
    NA
    Hairs on fruit
    the fruits are not hairy
    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
    1–1.4 mm
    Seed number
    12–26
    Seed surface
    • the seed is covered with reticulate markings (a netlike pattern due to splitting and rejoining of lines or ridges)
    • the seed is smooth or without clear markings
    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 more than two years
    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
    Underground organs
    the plant has a caudex (the root mass is firm and hardened at the top)

  • 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
    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
    alternate: there is one leaf 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 is entire (has no teeth or lobes)
    Leaf blade flatness
    the leaf is flat (planar) at the edges
    Leaf blade hairs
    the leaf blade has branched hairs
    Leaf blade length
    20–40 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)
    • the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
    • the leaf blade is oblong (rectangular but with rounded ends)
    Leaf blade surface colors
    the upper side of the leaf blade is relatively uniform in color
    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)
    Leaf blade width
    3–10 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 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
    1–3 mm
    Leaf teeth and lobes
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf type
    the leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
    Leaf types
    • NA
    • 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 (i.e., lobed or unlobed but not separated into leaflets)
    Stipels
    NA
    Stipule features
    NA
    Teeth per side of leaf blade
    0

  • Place

    Habitat
    terrestrial
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • grasslands
    • man-made or disturbed habitats
    • meadows or fields
    • sandplains or barrens
    • woodlands

  • 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 circular, or with lots of small angles so that it is roughly circular
    Hair between stem nodes
    the stem has hairs between the nodes
    Hairs between stem nodes
    at least some of the hairs on the stem are branched
    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
    20–50 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 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

Distribution

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

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

Massachusetts
fairly widespread (S-rank: S4S5)
Vermont
rare (S-rank: S2), threatened (code: T)

From Flora Novae Angliae dichotomous key

1.  Crocanthemum bicknellii (Fern.) Barnh. N

hoary frostweed. Crocanthemum majus, sensu Britt.; Helianthemum bicknellii Fern. • CT, MA, ME, NH, RI, VT; largely absent from extreme northern New England. Open, sandy soils 
of woodlands, roadsides, clearings, dry fields, and sandplains. Flowering ca. 10–15 days 
later than Crocanthemum canadense when both are present at the same site.

Native to North America?

Yes

Sometimes confused with

Crocanthemum canadense:
open-pollinated flowers (i.e., the larger ones) solitary or paired at the summit of the stem during flowering, overtopped by lateral branches later in the season, capsules of the closed-pollinated flowers (i.e., the smaller ones) with 5-10 seeds (vs. C. bicknellii, with open-pollinated flowers (i.e., the larger ones) in a flat-topped array of 2-20 flowers at the summit of the stem during flowering, usually not overtopped by lateral branches later in the season, capsules of the closed-pollinated flowers (i.e., the smaller ones) with usually 1 or 2 seeds).
Crocanthemum propinquum:
aerial stems scattered along a creeping rhizome, outer sepals of cleistogamous flowers apically distinct for distance of 0.2-0.5 mm, and capsules of cleistogamous fruits somewhat round in cross-section (vs. C. bicknellii, with aerial stems +/- clustered at the tips of caudex branches, outer sepals of cleistogamous flowers apically distinct for distance of usually 0.6-0.1.2 mm, and capsules of cleistogamous fruits sharply 3-angled in cross-section).

Synonyms

  • Crocanthemum majus, in the sense of Britt.
  • Helianthemum bicknellii Fern.

Family

Cistaceae

Genus

Crocanthemum