Cresses, Mustards, Cabbages & Allies
What are they?
A large family of annual and perennial herbaceous plants with white, yellow or pinkish-purple petals. Flowers have four petals, but in some species, the petals are deeply cleft, giving the appearance of there being eight petals. This family contains a number of crop plants, including Cabbage (and all its forms), Oil-seed Rape, Turnip and many others.
Where are they found?
Being a large family, there are species to be found in most habitats, though with many species being introduced from Europe, urban and cultivated areas tend to have the most species.
Identification
Many species can be most easily identified by their seed pods, sometimes in combination with the leaf shape. Many species have leaves of two types - those in the basal rosette and those on the upper stem. It can be important to make a note of the appearance of both of these.
Spring Whitlow-grass Draba verna
Introduced from Europe and now a common annual in dry habitats, especially in lawns and gardens and often found growing from cracks in pavement. Flowers March to June. A tiny plant, often no more than an inch high. Petals are deeply cleft and seed pods are flattened and round.
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Sweet Alison Lobularia maritima
(Sweet Alyssum) Introduced from Europe. A popular garden plant which occasionally grows as a pavement or border weed in urban areas, but may not survive harsher winters. Flowers March to July, often much later. A low growing plant which may form low, tight humps of vegetation, or trail down from raised borders.
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Shepherd's Purse Capsella bursa-pastoris
Introduced from Europe. Perhaps overlooked by earlier botanists as there are no published Cape May records, this is a widespread and common weed of disturbed ground, epsecially in urban environments. Flowers April to July, often much later. Best told by its distinctive, narrowly heart-shaped seed pods; these are the 'shepherd's purses' of its name.
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Field Pepperwort Lepidium campestre
(Field Peppergrass) Introduced from Europe. Occasional in waste and disturbed places, grassy roadsides and field margins. Flowers April to July. Forms a narrow, upright spike with leaves that clasp the stem. Seed pods spoon-shaped.
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Narrow-leaved Pepperwort Lepidium ruderale
(Roadside Peppergrass) Introduced from Europe. A small, easily overlooked species that seems to favor growing from roadsides, cracks in pavement and other similar places. Flowers May to September. Leaves mostly parallel-sided and grass-like, but some with one or two pointed side lobes.
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Virginia Pepperwort Lepidium virginicum
(Virginia Peppergrass) A widespread and often common weed of many kinds of waste, disturbed and rough places. Flowers April to November. Note that basal and stem leaves are very different in appearance with the basal leaves oftening reddening or dying off before flowering.
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or wither before flowering |
Common Pepperwort Lepidium densiflorum
(Common Peppergrass) A widespread and common weed of many kinds of waste, disturbed and rough places. Flowers May to June. Similar in overall appearance to Virginia Pepperwort, but often larger with more side branches and flowers have much smaller petals, the petals sometimes even absent.
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Lesser Swinecress Lepidium didymum
Introduced from Europe. Known from other locations in New Jersey but first reported from Cape May County in 2012, on waste ground in Avalon. Flowers March to June. An unimpressive little plant that trails across the ground. The greatly reduced petals may only be noticed with a hand lens.
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Shepherd's Cress Teesdalia nudicaulis
This small, European species is not noted in any publications for Cape May County, but is currently known to occur in short grass at sites scattered thrroughout the county. Flowers March to May. A tiny plant, often found in close colonies of flowering stems.
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Umbellate Candytuft Iberis umbellata
Introduced from Europe. Often a constituent of so-called 'wildflower mixes' and occasionally persists for a while where sown in disturbed or grassy places. Flowers June to September. A small plant, but flowers are often brightly-colored and eye-catching. Flowers may be white, or any shade of pink or purple. Petals are of unequal size, with two smaller petals and two larger ones.
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Evergreen Candytuft Iberis sempervirens
Introduced from Europe. May occasionally be found as an escape from cultivation or where deliberately planted in coastal dunes. Flowers April to June. A perennial species which forms low mounds of dark green vegetation. Flowers white but sometimes are tinged pink as they fade.
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Field Pennycress Thlaspi arvense
An arable weed introduced from Europe and now occasionally found on any type of disturbed or waste ground. Flowers May to October. The smooth, shiny leaves and large, flattened seed capsules are distinctive.
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Garlic Pennycress Thlaspi alliaceum
An arable weed introduced from Europe and now occasionally found on any type of disturbed or waste ground. Flowers March to June. Differs from Field Pennycress in its inflated (not flattened) seed capsules and its clasping leaf bases.
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Garlic Mustard Alliaria petiolata
Introduced from Europe. Widespread and quite common, especially where ground has been disturbed in open woodland and other shady spots. Flowers April to May. Plant has a garlic smell to it. Young leaves emerge in late winter and have a slightly silvery look to them.
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Thale Cress Arabidopsis thaliana
Introduced from Europe. A widespread and common annual in all sorts of open, dry locations. Flowers March to May. Always a thin and spindly plant and easily overlooked, but often occurs in colonies. Basal rosette leaves rough, upper parts of plant smooth. Seed pods not held close to the main stem.
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Creeping Yellowcress Rorippa sylvestris
Introduced from Europe. Uncommon and found in wet soil and boggy ground. Flowers May to June. Unlike most members of the family, this species has a creeping root system and forms mats of flowering stems. Similar to Marsh Yellowcress but note the differences in the leaves.
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Marsh Yellowcress Rorippa palustris
(Marsh Watercress) Occurs in a few places in damp, muddy edges to swamps and marshes. Flowers April to June. Similar to Creeping Yellowcress but note the differences in the leaves.
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Common Watercress Nasturtium officinale
Introduced from Europe. An uncommon plant, still found in a few places where it was previously introduced in muddy streams. Flowers May to July. Forms solid mats of vegetation in wet mud and streams, especially in steadily-flowing water.
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Hedge Mustard Sisymbrium officinale
Introduced from Europe. Uncommon but occasionally found on areas of disturbed ground and waste places. Flowers May to September. A rather wiry plant with less succulent stems than most related species. As the season progresses, flowering stems gradually elongate to produce long, spindly side branches. Flowers rather small and not as showy as other species.
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Early Wintercress Barbarea verna
Introduced from Europe. Occasional in damp soils in open places. Flowers April to June. Upper leaves are deeply cut into narrow lobes.
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Common Wintercress Barbarea vulgaris
(Yellow Rocket) Introduced from Europe. Uncommon in open fields and other waste places. Flowers April to July. Upper leaves are entire (unlobed) with toothed margins.
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Honesty Lunaria annua
Introduced from Europe. Commonly grown in gardens, from where it often spreads to nearby roadsides, field edges and woodland. Flowers April to June. Flowers may be lilac or white. After seeds have dropped, the silvery membrane left behind is readily recognized.
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Dame's-violet Hesperis matronalis
(Dame's Rocket) Introduced from Europe. Occasionally grown in gardens and sometimes escaping into nearby hedgelines and roadsides. Flowers May to June. Flowers may be purplish or white and the plant resembles the much more common Honesty. However, it can be told from that species by its narrower leaves and seed capsules.
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Drummond's Rock-cress Arabis drummondii
This plant is currently known from just a single site in New Jersey, off Sunset Boulevard in Cape May Point. Flowers April to May. Though the plant is considered to be a very rare native on the strength of this single known occurence here, the species is generally found in rocky ground, a habitat missing in Cape May. The current location is suspiciously close to the old Cape May Magnesite plant and it seems to me that this species was accidentally introduced to the area from further west, perhaps in railway ballast or other stone products such as coastal defences.
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double row |
Hairy Bittercress Cardamine hirsuta
Introduced from Europe. Widespread and very common in all kinds of open and disturbed habitats; often abundant in bare patches on lawns and in flower borders and may be a serious weed in nurseries and garden centers. Flowers mostly March to May but occasionally in other months too. The fine hairs (hand lens needed) on the petioles of the basal leaves distinguish this species from the other Cardamine species.
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developed at flowering |
leaf base |
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Pennsylvania Bittercress Cardamine pensylvanica
A small plant of shady wetlands and damp woods. Flowers April to July.
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at flowering |
leaf base |
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Sand Bittercress Cardamine parviflora
Found in a few locations in usually dry, shady, sandy soil. Flowers April to July.
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Cabbage Brassica oleracea
Introduced from Europe. Occasionally found as a relic of cultivation, on waste ground or abandoned land, but usually short-lived. Flowers May to July, sometimes later. Flowers are typically larger and paler yellow than most other members of the family. The garden cabbage is just one of many selectively-bred forms that all originate from a single species. Brussels Sprouts, Kohlrabi, Calabrese, Broccoli and others are all forms of the same species.
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Turnip Brassica rapa
(Field Mustard) Introduced from Europe. Occasionally found as a relic of cultivation, on field borders and roadsides. Flowers May to July. When in flower, the open flowers overtop the flowers still in bud, leaving a 'hollow' center to the flowering head.
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Wild Radish Raphanus raphanistrum
Introduced from Europe and now a common weed of arable fields and other cultivated and disturbed areas. Flowers May to November. Flowers may be pale yellow or white, usually with darker veins. Leaves coarsely hairy.
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American Sea Rocket Cakile edentula
A common plant of sandy beaches, usually growing along the storm tide line at the back of the beach. Sometimes also on open saltmarsh areas. Flowers June to October.
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