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

Arabis pycnocarpa — hairy eared-rockcress

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New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Facts

Hairy eared-rockcress is native to North America as well as China, Japan, and eastern Russia. In New England it is found on ledges, outcrops, and calcareous rocky woodlands.

Habitat

Cliffs, balds, or ledges, ridges or ledges, talus and rocky slopes, woodlands

Characteristics

Habitat
terrestrial
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Vermont
Flower petal color
  • blue to purple
  • pink to red
  • white
Leaf type
the leaves are simple (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 has teeth
  • 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 four petals, sepals, or tepals in the flower
Fusion of sepals and petals
both the petals and sepals are separate and not fused
Stamen number
6
Stem nodes swollen
the stem is not swollen at the nodes
Fruit type (general)
the fruit is dry and splits open when ripe
Fruit length
30–50 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 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 length
    0.7–1 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
    Anther tube length
    0 mm
    Calyx growth after flowering
    the calyx does not grow 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)
    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
    Cleistogamous flowers
    there are no cleistogamous flowers on the plan
    Corolla morphology
    NA
    Corolla palate
    no
    Corona lobe length
    0 mm
    Epicalyx
    the flower does not have an epicalyx
    Epicalyx number of parts
    0
    Filament length
    2.5–4 mm
    Filament surface
    the filament is smooth, with no hairs or scales
    Flower appearance
    the flowers appear after the leaves have appeared
    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
    • blue to purple
    • 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 knob-like at the tip, and unbranched
    Fringed petal edges
    the petals are not fringed
    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
    • the flower stalk has no 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
    Interior flower disk
    the flower does not have an interior disc
    Length of flower stalk
    2–12 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
    2
    Number of pistils
    1
    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 rotate (platter-shaped, the corolla flattened, circular, with nearly horizontally spreading lobes)
    Petal and sepal arrangement
    the flower includes two cycles of petal- or sepal-like structures
    Petal and sepal colors
    • blue to purple
    • pink to red
    • white
    Petal appearance
    the petals are thin and delicate, and pigmented (colored other than green or brown)
    Petal base
    the petal narrows abruptly at the base
    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 hairs on inner/upper surface
    there are no hairs on the inner/upper petal surface
    Petal length
    3–5 mm
    Petal length relative to sepals
    the petals are longer than the sepals
    Petal nectaries
    the petals do not have nectaries
    Petal number
    4
    Petal shape
    • the petal outline is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
    • the petal outline is oblong (rectangular, but with rounded ends)
    • the petal outline is obovate (roughly egg-shaped, but with the widest point above the middle of the leaf blade)
    • the petal outline is spatulate (spoon-shaped; narrow near the base, then suddenly widening to a rounded tip)
    Petal tip shape
    the petal tip is obtuse (bluntly pointed)
    Petal tips (Cuscuta)
    NA
    Petal width
    1–2.5 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
    Sepal color
    green to brown
    Sepal features
    the sepals do not have any of the mentioned special features
    Sepal length
    2.5–4 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 oblong (rectangular, but with rounded 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 acute (is sharply pointed)
    • the sepal tip is obtuse (is bluntly pointed)
    Sepal uniformity
    all the sepals are about the same size
    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 length
    3.2–5 mm
    Stamen lengths differ
    the stamens are tetradynamous (four long stamens and two short ones)
    Stamen morphology
    the stamens within a cycle differ in length or width
    Stamen number
    6
    Stamen position relative to petals
    NA
    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 positioned at the tip of the style
    Style length
    0.2–1.3 mm
    Style petal-like
    the styles are not petal-like
    Style relative length
    NA
    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
    Capsule splitting
    • NA
    • the capsule splits by two main valves, teeth or pores
    Carpel beak length
    0 mm
    Fruit (pyxis) dehiscence
    NA
    Fruit beak length
    0 mm
    Fruit cross-section
    • the fruit is at least somewhat flattened
    • the fruit is round in cross-section
    Fruit features (Brassicaceae)
    NA
    Fruit length
    30–50 mm
    Fruit length relative to sepals
    NA
    Fruit length to width ratio
    37.5–38.5
    Fruit locules
    two
    Fruit shape
    • the fruit is flat or strongly compressed
    • the fruit is roughly cylindrical (with parallel sides that do not taper, and flat across the top and bottom)
    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 silique (greater than three times as long as wide, and dehisces by two valves, leaving the persistent replum to which the seeds are attached, found only in the Brassicaceae)
    Fruit width
    0.8–1.3 mm
    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
    Ovary stipe
    the ovary or fruit does not have a stipe
    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
    Relative fruit length
    0
    Rows of seeds in fruit (Brassicaceae)
    there is one row of seeds in each locule of the fruit
    Schizocarpic fruit compression
    NA
    Schizocarpic fruit segments
    0
    Seed length
    0.8–1.7 mm
    Seed relative length
    • the seed is about as long as it is wide
    • the seed is longer than it is wide
    Seed surface
    • the seed is covered with reticulate markings (a netlike pattern due to splitting and rejoining of lines or ridges)
    • the seed is hairless
    • the seed is smooth or without clear markings
    Seeds comose
    no hairs
    Septum in fruit (Brassicaceae)
    The fruit is either not compressed or is compressed parallel to the septum; therefore, the fruit and its septum are about the same width
    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 for two years
    • 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
    Plants darken when dry
    no
    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)
    • there is a thickened taproot on the plant
  • 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
    • the petiole has hairs on it
    • the petiole has no 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
    • the upper side of the leaf is not hairy, or it has very few hairs
    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)
    • the leaf has no stalk
    • the leaf has no stalk and at the base it clasps the stem
    Leaf blade base shape
    • the base of the leaf blade is cordate (heart-shaped, has rounded lobes at the base)
    • the base of the leaf blade is sagittate (arrow-shaped, with pointed lobes directed backwards)
    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 teeth
    • 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
    10–80 mm
    Leaf blade primary vein pattern
    the secondary veins branch off at intervals from the primary vein
    Leaf blade shape
    • the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
    • the leaf blade is linear (very narrow with more or less parallel sides)
    • 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)
    • the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
    • the leaf blade is spatulate (spoon-shaped; narrow near the base, then suddenly widening to a rounded tip)
    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 of the leaf blade branch, but do not rejoin
    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
    1–25 mm
    Leaf duration
    • the leaves drop off in winter (or they whither but persist on the plant)
    • the leaves remain green all winter
    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
    • the leaves have no leaf stalks, but attach directly to the stem
    Leaf stalk attachment to leaf
    • NA
    • the petiole attaches at the basal margin of the leaf blade
    Leaf stalk base
    • NA
    • the petiole base clasps the stem or sheathes the stem
    Leaf stalk length
    5–20 mm
    Leaf teeth and lobes
    • the edge of the leaf blade is entire (has no teeth or lobes)
    • the leaf blade margin has outward-pointing teeth
    • the leaf blade margin is wavy, but does not have teeth
    Leaf tip
    • the tip of the leaf blade is acute (sharply pointed)
    • the tip of the leaf blade is obtuse (bluntly pointed)
    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
    • the lower leaves are larger, toothier, and/or on longer stalks than the upper leaves
    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
  • Place

    Habitat
    terrestrial
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Vermont
    Specific habitat
    • cliffs, balds, or ledges
    • ridges or ledges
    • talus or rocky slopes
    • 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
    20–80 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

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

New England distribution and conservation status

Distribution

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

Conservation status

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

New Hampshire
extremely rare (S-rank: S1), endangered (code: E)

Native to North America?

Yes

Sometimes confused with

Boechera stricta:
petals 7-10 mm long, white to pink or rose-purple, basal portion of stem without hairs or these sparse, and fruits 1.5-3.5 mm wide (vs. A. pycnocarpa, with petals mostly 3.5-5 mm long, white, basal portion of stem moderately to densely pubescent, and fruits mostly 0.8-1 mm wide). Turritis glabra: petals yellow, fruits circular in cross-section, and stem without hairs (vs. petals white, fruits compressed, and stems hairy at least near the base).

Synonyms

  • Arabis hirsuta ssp. pycnocarpa (M. Hopkins) Hultén
  • Arabis hirsuta var. pycnocarpa (M. Hopkins) Rollins
  • Turritis oblongata Raf.

Family

Brassicaceae

Genus

Arabis

Notes on subspecies and varieties in New England

Our variety is Arabis pycnocarpa M. Hopkins var. pycnocarpa.

From the dichotomous key of Flora Novae Angliae

2.  Arabis pycnocarpa M. Hopkins var. pycnocarpa N

hairy eared-rockcress. Arabis hirsuta (L.) Scop. ssp. pycnocarpa (M. Hopkins) Hultén; A. hirsuta (L.) Scop. var. pycnocarpa (M. Hopkins) Rollins; Turritis oblongata Raf. • CT, MA, ME, NH, VT. Ledges, rock outcrops, rocky woodlands, in regions of high-pH bedrock. Arabais pycnocarpa, which is native to North America, is frequently treated as an infraspecific form of the European Arabis hirsuta. However, the two taxa differ in geographic range, ploidy level, fruit length and venation, style morphology, and seed number (i.e., ample justification exists for recognition of two species).