Short, White Brassicas With Round Seed Pods

Field Penny-cress English Scurvygrass Early Scurvygrass Garlic Penny-cress

What are they?

This page covers members of the brassica family that typically grow less than 50cm in height and have white - usually rather small - flowers. They all share the same general appearance of four-petalled, white flowers that are followed by short, rounded seed pods that may be either globular, or flattened. For identification purposes, it is wise to wait until seed pods have started to develop, as this will help to narrow your search.

Where are they found?

This is a group of only loosely related plants, so there is much variation in the habitat choices, from urban habitats to roadsides, heaths and wetlands. However, the habitat can be a valuable aid to identification for some species - especially the coastal ones, so be sure to check these details in the individual species notes below.

Identification

All these plants have white, four-petalled flowers and rounded seed pods, so you need to look elsewhere for identification clues. Most important will be details of the leaves - both basal and those on the flowering stems, while tiny differences in the flowers and the pods can help with closely related species. As noted above, the habitat and location is also useful to note.



Field Penny-cress      Thlaspi arvense

An ancient introduction of disturbed ground, common and widespread in arable areas, gardens and other bare ground. Flowers May to July, sometimes later. A variable plant with a compact head of tight flowers, that elongates greatly as the flattened, disc-like seed pods appear.

Field Penny-cress Field Penny-cress Field Penny-cress Field Penny-cress
Habit
Flowers
Leaf
Seed pod


Garlic Penny-cress      Thlaspi alliaceum

A recent introduction from Europe. A handful of records since the 1990s but remaining rare as a non-established casual in gardens. Flowers May to July, sometimes later. Flowers rarely open fully; stem leaves clasping at the base. Seed pods differ from those of Field Penny-cress in having a much smaller 'winged' edge and in being globular rather than flattened and disk-like.

Garlic Penny-cress Garlic Penny-cress Garlic Penny-cress Garlic Penny-cress
Flowers
Stem leaf
Seed pod
Seed pod


Common Whitlowgrass      Erophila verna

A native annual; common and widespread and found on all kinds of dry, open areas, including sandy soil, pavement cracks and on walls. Flowers March to May. Tiny plants that are often no more than 4-5cms tall and thus easily overlooked, but often common and forming quite extensive colonies. The tiny, white flowers have very deeply divided petals, while the basal leaves are usually covered in stiff, white hairs which extend up the basal part of the flowering stem. Note that these hairs can wear off, making identification more difficult later in the season. Seedpods oval in outline and greatly flattened, like a deflated rugby ball. Separation from the much rarer Glabrous Whitlowgrass is very difficult; leaves have petioles 0.5-1 times as long as the leaf-blade and petals are notched more than half way to the base.

Common Whitlowgrass Common Whitlowgrass Common Whitlowgrass Common Whitlowgrass
Habit
Flowers
Basal leaves
Seed pods


Glabrous Whitlowgrass      Erophila glabrescens

A native annual; rare in dry, open sites on sandy soil, along roadsides and even on old walls. Flowers March to May. Tiny plants that are often no more than 4-5cms tall and thus easily overlooked. Extremely similar to Common Whitlowgrass and difficult to tell from it. The whole plant is typically hairless, leaves have petioles 1.5-2.5 times as long as the leaf-blade (though beware of very young plants still developing) and petals are notched less than half way to the base.

Glabrous Whitlowgrass Glabrous Whitlowgrass Glabrous Whitlowgrass
Habit
Flowers
Basal leaves


Early Scurvygrass      Cochlearia danica

(Danish Scurvygrass) Native annual of coastal habitats in drier parts of saltmarsh and in sandy locations, including in towns. Since about the early 1980s, this species has rapidly colonised the bare edges of major roads throughout the region where salting occurs during the winter months. Often forms extensive colonies of low mounds of white or pinkish flowers along major duel carriageways. Flowers March to June. Leaves more angular, less rounded than those of other scurvygrasses; upper leaves without stalk, but not clasping the stem. Seed pods globular, narrowed at both ends.

Early Scurvygrass Early Scurvygrass Early Scurvygrass Early Scurvygrass
Habit
Flowers
Leaf
Seed pod


English Scurvygrass      Cochlearia anglica

Native biennial or short-lived perennial found in coastal saltmarshes. Flowers April to July. Basal leaf blades taper into the petiole at the base. Upper leaves unstalked, clasping the stem. Seed pods flattened oval.

English Scurvygrass English Scurvygrass English Scurvygrass English Scurvygrass
Habit
Flowers
Leaf
Seed pod


Common Scurvygrass      Cochlearia officinalis

Native biennial or short-lived perennial found in coastal saltmarshes. Flowers May to August. Despite the English name, this is the least common of the three scurvygrasses in our region. Basal leaf blades rounded at the base, upper leaves unstalked, clasping the stem. Seed pods globular, oval.

Common Scurvygrass Common Scurvygrass Common Scurvygrass
Habit
Flowers
Leaf


Sweet Alison      Lobularia maritima

Introduced from Europe. Very popular as a garden annual and occasionally self-seeding outside of gardens. Now well established in milder, coastal areas where it most often grows from walls and in dry locations. Flowers April to September. Forms low-growing mounds with flowers lasting well through the season. Leaves narrow, greyish-hairy.

Sweet Alison Sweet Alison Sweet Alison Sweet Alison
Habit
Habit
Flowers
Leaves


Sea Rocket      Cakile maritima

An annual plant which occurs commonly right on the strandline on open, sandy or shingly beaches. Flowers June to September. A straggly plant with deeply-lobed, fleshy leaves and white or very pale pink flowers.

Sea Rocket Sea Rocket Sea Rocket Sea Rocket
Habit
Flowers
Leaves
Seed pods


Hoary Alison      Berteroa incana

Introduced from Europe. Rare in our region but long established in one or two locations in the Breckland area. Flowers June to August. A slender plant, growing to 60cm but often shorter. The whole plant is covered in dense, star-shaped hairs.

Hoary Alison Hoary Alison Hoary Alison Hoary Alison
Habit
Flowers
Leaf
Seed pods