The Dull-Flowered Sweet Clover or Alpine Sainfoin
(HEDYSARUM OBSCURUM)
The Alpine Sainfoin is the only member of the sixteen European species of Hedysarum (Sainfoin) that is found in Switzerland. The plant consists of a thick, dense underground stem which persists from year to year and serves as a storehouse for food. Underground branches extend outward from this in various directions and give rise to ascending shoots bearing leaves and flowers. The short stalked leaves bear eleven to nineteen leaflets which are arranged in pairs; the purple-red flowers occur in clusters. The flowers are visited by bees on account of the honey they contain. By means of a sort of catapult arrangement, which only goes off when the bee settles on the flower, the body of the insect becomes dusted with pollen and as the bee travels from flower to flower pollination is effected. In the Western Alps a variety of this plant with yellowish flowers is occasionally to be found. The seed vessel of the Alpine Sainfoin is very characteristic. It is not unlike an ordinary pea-pod, but is smaller, more flattened, and divided into two or three oval segments by constrictions. The plant is fairly abundant between 5000 and 8000 feet, and flowers in July and August. It is rare in meadows, but is found on the rocky borders of Alpine pastures and on the banks of streams. It is met with in all parts of the Alps, in the mountainous districts of Europe and Asia, and in the Arctic regions, and is thought to have taken origin in the Steppes of Northern Asia. It should be very easily recognised. The drooping habit of the flowers and the constricted seed-pods are most characteristic.
The flowers of this species have generally more red in them than those of the specimen photographed.
Plate XIV.
HEDYSARUM OBSCURUM. L.
The Dull-Flowered Sweet Clover or Alpine Sainfoin. Esparcette des Alpes. Dunkler Süssklee.