Brassicaceae: Mustard Family — Fringepods & Peppergrass

Members of the mustard family all have four petals, usually in a cross shape (hence Cruciferae; the old name for the family).  With some groups, the flowers are quite similar, so it helps to pay close attention to the fruits.  This is especially true for the mustards themselves (Brassica, Hirschfeldia, Sisymbrium, Caulanthus and Turritis).

Fruits in the Mustard family are of two kinds, siliques and silicles.  Siliques are at least twice as long as they are wide, while silicles are less elongated.  Some silicles are erect and appressed to the stem, others grow outwards and curve upwards, or outwards and curve downwards.  All the plants on this page have more or less flattened silicles, of different shapes and degrees of hairiness, some notched at the tip, some not.

Shepherd’s Purse – Capsella bursa-pastoris

Blooms:

Jan–Oct

Plant Height:

15–50 cm

Flower Size:

Very small

Origin:

Eurasia

Habitat:

Disturbed areas

Notes:

A very common weedy cress, distinguished by its heart shaped fruits.  When ripe, these split down the middle, releasing yellow seeds which are sometimes likened to golden coins in a shepherd’s purse.

Spring / Vernal Whitlow-grass – Draba verna

Blooms:

Feb–May

Plant Height:

5–20 cm

Flower Size:

Very small

Origin:

Europe

Habitat:

Open or disturbed places

Notes:

At first sight similar to the peppergrasses, but can be distinguished first by its rosette of small hairy basal leaves, and second by its fruit.   These are silicles, variable in shape from elliptic or ovate to oblong or even linear, and lacking the notched tip characteristic of peppergrasses.  The four white petals are deeply cleft.

English Peppergrass – Lepidium campestre

Blooms:

May–July

Plant Height:

12–50 cm

Flower Size:

Small clusters

Origin:

Europe

Habitat:

Meadows & woodland

Notes:

The most distinctive feature of this peppergrass is the elongated inflorescence with its small, spoon-shaped flowers forking off the stem. Fruits are flat, oblong to ovate and notched at the tip. There is a basal rosette of leaves as well as oblong to lanceolate cauline leaves. The entire plant is covered in short hairs.

Lesser Swine Cress – Lepidium didymum

Blooms:

Mar–June

Plant Height:

10–45 cm

Flower Size:

Very small

Origin:

Europe

Habitat:

Disturbed areas

Notes:

A common weed in disturbed places, more closely related to the peppergrasses than to the cresses, despite its common name. The leaves are finely dissected, the lobes entire or themselves lobed.  The fruits are the most distinctive feature, in pairs resembling a rather small pair of spectacles.

Shining Peppergrass – Lepidium nitidum

Blooms:

Feb–Mar

Plant Height:

10–35 cm

Flower Size:

Very small

Origin:

Native

Habitat:

Open grassland and slopes

Notes:

The tiny white flowers are less distinctive than the fruits.  They are flattened, shiny ovals with a shallow notch at the tip, and a conspicuous vertical seam down the middle.  Fruits are green, maturing red.  The pedicel itself is strongly flattened.

Upright Pepperweed / Wayside Peppergrass – Lepidium strictum

Blooms:

Apr–June

Plant Height:

7–17 cm

Flower Size:

Very small

Origin:

Native

Habitat:

Generally in hard-packed soil

Notes:

A smaller, very leafy peppergrass with similar fruits to Shining Peppergrass (Lepidium nitidum, see above), but smaller and with a more pronounced notch at the tip.  Leaves are pinnate with slender leaflets.

Hairy Fringepod – Thysanocarpus curvipes subsp. curvipes & elegans

Blooms:

Feb–June

Plant Height:

10–60 cm

Flower Size:

Very small

Origin:

Native

Habitat:

Grassy or brushy slopes

Notes:

As a group, Fringepods are most easily recognized by their fruits, oval with more or less crenate (scalloped) margins, perforated or not.  This plant has hairy fruits, with wings which may be perforated or just crenate.  It is distinguished from Narrow-leaved Fringepod (Thysanocarpus laciniatus, see below) by the clasping base of its leaves.  There are two slightly different subspecies; subsp. elegans, which has fruits 6 mm long or more, and consistently perforated wings; and subsp. curvipes, which has  smaller fruits, less than 6 mm long, with wings which may be perforated or just crenate.

Narrow-leaved Fringepod – Thysanocarpus laciniatus

Blooms:

Mar–May

Plant Height:

10–60 cm

Flower Size:

Very small

Origin:

Native

Habitat:

Open places

Notes:

As a group, Fringepods are most easily recognized by their fruits, oval with more or less crenate (scalloped) margins, perforated or not.  This species has fruits that are smaller (3–5 mm), not hairy and are rarely perforated.  Its leaves do not have clasping bases, and may be pinnately lobed. The glabrous fruits and non-clasping leaves make it easy to distinguish this species from Hairy Fringepod (Thysanocarpus curvipes, see above).  The photo on the right shows the fruits of both Narrow-leaved and Hairy Fringepods, to show the difference in size and hairiness.