FABACEAE 

 

There are a surprising number of different kinds of leguminous plants on the Ham Lands. Several species are uncommon or rare in the London area and many are attractive. We are lucky to have such a splendid diversity.

How to recognise Legumes? They all have: –

-Pea-like flowers with special kinds of petals: – an upper standard, 2 wings on either side, and a keel (boatshaped petal) sitting between the wings.

-Pods containing seeds, which resemble beans or pea-pods.

-Compound leaves (each leaf is made up of leaflets); stipules (often small triangular structures) found at the base of the leaf stem; sometimes tendrils are present (as part modified leaf structures). The number of leaflets varies in different groups as does the size and shape of the stipules. This helps with identification but in a few cases things can appear misleading and the explanations tricky.

VETCHLINGS AND EVERLASTING PEAS (LATHRUS) – These tend to be sprawling plants with square stems either angled or winged. They have 0–1(2) pairs of leaflets, most have tendrils. The pods are like small pea-pods.

Yellow Vetchling Lathrus aphaca. This uncommon native species is fairly well represented on the HL South and easily recognised by its greyish foliage. Some explanation is required as it is one of the tricky examples: it has no leaflets, just a single tendril. The stipules are large and triangular-oval and function like leaves. The flower stalks bear only one yellow flower. Flowering from late May.

Grass VetchlingLathrus nissolia. This native species is relatively rare, but can usually be found at Ham, especially HL South. When not in flower it is hard to spot because the grass-like blades merge with the sward. Again it is a tricky example. The blade is actually a phyllode (a modified leaf-stalk), there are neither leaflets nor tendrils, and the stipules are minute. The dainty flower stalks are relatively long and bear 1–2 bright crimson flowers. Flowering from late May.

Meadow VetchlingLathrus pratensis. This native species is a relatively common, but attractive member of the HL flora. It has one pair of leaflets, tendrils are present and the stipules are arrow-shaped. There are 5–12 yellow flowers. Flowering from late May.

 

From the left side: Yellow Vetchling, Grass Vetchling, Meadow Vetchling 

Broad-leaved Everlasting Pea Lathrus latifolius. This introduced species is very common in the UK, being especially abundant along railway lines. It is by far Ham’s largest and most showy Lathrus. The stems are distinctly winged. It has one pair of leaflets and both tendrils and stipules. There are 3–12 bright magenta flowers per stalk, but an albino form can occasionally be found at Ham. Flowering from June.

Two further species of Lathrus have been recorded at Ham, but are rare.

Hairy Vetchling Lathrus hirsutus. This is similar to the everlasting Pea but much smaller. The flowers have a red-purple standard and pale blue wings, and the pods are hairy. It occurs on HL north.

Narrow-leaved Everlasting PeaLathrus sylvestris. Similar to the Broad-leaved Everlasting Pea but smaller, the leaflets are narrower and the flowers buff/yellow to pale rose-pink. If anyone does find one please let us know. We will be delighted.

 

       

From left: Broad-leaved Everlasting Pea leaves and flower, Hairy Vetchling flower

 

 3) More than 2 pairs of leaflets and tendrils – the genus Vicia

 Vetches and TaresVicia   These plants are normally sprawling to somewhat climbing, with round or ridged, un-winged stems. They have 3–15 pairs of leaflets, tendrils and small stipules. The pods are pea-like in miniature.

 

                                   

                                            Common Vetch                                                 Tufted Vetch

 

Common Vetch – Vicia sativa subsp. segatalis. This common species is scattered throughout the Ham Lands and is the first to flower. It has 4–8 pairs of opposite leaflets. There are 1–2 magenta-purple flowers on a short stalk. Flowering time from April.

A similar species Bush Vetch - Vicia sepium differs by being a downy plant with broader leaflets, and 2–6 duller coloured flowers. It is very rare at Ham and not seen recently.

Tufted Vetch – Vicia cracca. Culmps of this showy native species are frequently found at Ham. There are 8–15 pairs of leaflets. The blue-purple flowers are in heads of 10–40. Flowering from June.

 A closely related species Fine-leaved Vetch – Vicia tenuifolia (differing by narrower leaflets and larger flowers with pale wings) has been recorded at Ham in the past.

The name ‘tares’ as in the Biblical – ‘separate the wheat from the tares’ – is commonly used for the following two species, although it can also be used for other Vicia species. You will notice that, now a days, these two species are considered to belong to different genera. The differences are slight and reasons are very academic and dull.

 

 

 

 

 

          Hairy Tare                                                                     Smooth Tare

 

 Hairy Tare – Ervilia (= Vicia) hirsute. This small-flowered, common native species is abundant on the Ham Lands, and often found tangled with other plants. There are 4–10 pairs of dainty alternate (not opposite) leaflets; There are 1–9, white, mauve veined, flowers per stalk; the calyx teeth are all equal in length. The hairy pods are 2-seeded. Flowering from May.

Smooth Tare – Erevium (= Vicia) tetraspermum. This species is very similar to the Hairy Tare and the two often grow together. It has fewer (3–6) pairs of alternate leaflets; the tendrils are usually not branched (unlike our other 3 Vicia species). There are fewer (1–2), flowers per stalk, these are slightly bigger and pale blue to lilac with purple veins; the lower calyx teeth are longer than the rest. The hairless pods are 4-seeded. Flowering from May

4) 5 leaflets, 1 pairs at the base of the stem and 3 at the top; stipules minute – the genus Lotus

Bird’s-foot Trefoils – Lotus These plants are cushion-like or sprawling. The leaves are another tricky example. Because the basal pair of leaflets can easily be mistaken for stipules the upper three can be interpreted as a trefoil (trifoliate) leaf. The true stipules are minute and hard to see. The flowers are grouped at the top of a slender stem above a small trifoliate leaf (or bract). The long, straight pods contain many seeds.

 

 

 

 

Common Bird’s-foot Trefoil

 Common Bird’s-foot Trefoil – Lotus corniculatus var. corniculatus. This native, common, jolly looking species is low growing and often cushion-like. There are 3–8 flowers in each head; each flower is bright yellow with red markings, giving rise to the common name ‘Eggs and Bacon’. The more familiar common name ‘Bird’s-foot Trefoil‘ alludes to the resemblance to bird’s feet of the grouped pods. Flowering from June.

Alien Bird’s-foot Trefoil – L. corniculatus var. sativa. This introduced fodder plant is very similar to our native variety. It differs by being weakly erect, often with hollow stems and the flowers lack red colouration. Flowering from June.

Slender Bird’s-foot Trefoil – Lotus tenuis. This rare native species has been recorded in Ham Lands, North but has not been seen recently as far as we know. It is a more up right plant with distinctly narrower leaflets. The pale yellow flowers are fewer (2–4) per head. Flowering from June.

Text and drawing by Diane Bridson