White brassicas with pronged seed pods
What are they?
This page covers members of the brassica family that typically grow less than 50cm in height and have white flowers. They all share the same general appearance of four-petalled, white flowers that are followed by short seed pods that may be either flattened evenly in one plane, or have upturned edges, making them rather like little shovels. All have tips that are clearly pointed with either one, two or three points, or spikey projections. For identification purposes, it is wise to wait until seed capsules 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, though most are plants of urban habitats and disturbed ground. However, the habitat can be a valuable aid to identification for some species, so be sure to check these details in the individual species notes below.
Identification
All these plants have rather distinctive seed capsules and attention to the shape of these, together with leaf and flower details should help to identify the species.
Common Shepherd's-purse Capsella bursa-pastoris
An ancient introduction of disturbed ground, widespread and often abundant in arable areas, gardens and other bare ground. Flowers more or less throughout the year. Readily identifiable by its basal rosette of sharply pinnate leaves and distinctive, heart-shaped seed capsules with parallel or slightly convex sides.
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Pink Shepherd's-purse Capsella rubella
Introduced from southern Europe. A rare casual of open places but peristing only at a single fenland site in Cambridgeshire. Despite the name, the pink flush often present on the flower buds is not completely reliable as an identification feature. This plant differs from Shepherd's-purse in its shorter petals (not much longer than the sepals) and in the concave sides to its seed capsules.
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concave sides |
Shepherd's Cress Teesdalia nudicaulis
An annual of open, sandy soil being mostly confined to Breckland and the Suffolk Sandlings, with a few isolated records from sandy soil elsewhere. Flowers April to June. A tiny plant and thus rather easily overlooked. Once found, the assymetrical flowers with two lower petals larger than the upper two, the shovel-shaped seed capsules and the neatly round-lobed leaves make a diagnostic combination.
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Perfoliate Penny-cress Noccaea perfoliata
(Microthlaspi perfoliatum) A rare native in the Cotswolds, but in East Anglia only recorded once in Suffolk, as an introduction from the continent. Flowers March to May. Flowers rarely open fully; stem leaves clasping at the base. Rather similar to Shepherd's-cress in its seed capsules, but a taller plant (to 20cm in height) and with distinctive, arrow-shaped leaves that clasp the stem.
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Perennial Candytuft Iberis sempervirens
Introduced from southern Europe as a garden rockery plant and rarely escaping into the wider countryside on walls and dry banks. Flowers April to June. An evergreen, perennial species, more or less becoming a woody sub-shrub over time. Leaves are deep, emerald green and the whole plant becomes covered in brilliant white flowerheads in late spring.
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Small Candytuft Iberis amara
Introduced from southern Europe as a garden annual and more recently a component of so-called 'wildflower mixes' that occasionally get scattered along roadsides and in other public places. Flowers July to September. A short-lived annual, differing from Evergreen Candytuft in its smaller, annual growth, more elongate heads of flowers, well-toothed leaves and more rounded seed capsules.
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