Large Hop Trefoil
- Name also: Golden Clover, Large Hop Clover
- Family: Pea Family – Fabaceae (Leguminosae)
- Growing form: Biennial herb.
- Height: 15–35 cm (6–14 in.). Stem erect, branched at base, smoothly haired.
- Flower: Corolla zygomorphic, initially golden yellow, finally yellowish brown, 6–7 mm (0.24–0.28 in.) long, fused at base. Petals 5; the upstanding the ‘standard’, the lateral two the ‘wings’, the lower two united to form the ‘keel’, overall shape of corolla being butterfly-like, standard notched. Calyx 5-lobed, fairly glabrous. Stamens 10. A single carpel. Inflorescence a long-stalked, 12–20 mm, (0.5–0,8 in.) long, racemose head.
- Leaves: Alternate, stalked, stipulate. Blade with 3 leaflets, leaflets elliptic, shallowly toothed, terminal leaflet unstalked. Stipules lanceolate, mainly united with stalks, same length as or longer than leaf-stalks.
- Fruit: Indehiscent pod, remains inside calyx.
- Habitat: Dry meadows, meadows, roadsides, banks.
- Flowering time: July–August.
- Endangerment: Near threatened.
Clover’s generic name Trifolium refers to the plants’ three-parted leaves. This feature is not unique to clover, however, and the name has been used for other plants in the past, but clover is the best known three-leaved plant and has been its most popular symbol throughout the ages: e.g. the suit of clubs in playing cards was originally clover. It was also known colloquially in Finland as cross-leaf. As Christianity spread to Finland clover began to be seen as a symbol of the Holy Trinity, and it evolved into a protective amulet to keep the bearer from harm.
Large hop trefoil is one of the most beautiful members of genus Trifolium that grows in Finland, and it probably arrived in Finland before Christianity. The species has apparently exploited burn-beat agriculture as its Finnish heartland is southern Karelia and Savo, where that kind of farming survived longest. Its most typical habitats include old burn-beat meadows beside rivers and roadsides in eastern Finland. On the other hand it doesn’t grow in really dry meadows. It seems to avoid calciferous land.
Large hop trefoil’s golden yellow flowers attract insects but it seems to be mainly self-pollinating, which is not really typical of clover. Large hop trefoil is the most common yellow-flowered clover species in Finland, but it has become rarer in its former territories as a consequence of the overgrowth of agricultural land; at the same time, however, it has spread to some new habitats. It differs from Finland’s other yellow-flowered clovers lesser hop trefoil (T. dubium) and hop trefoil (T. campestre) e.g. with regards to its leaves: large hop trefoil’s terminal leaflet is stalkless while the others’ are stalked.