Agri Kultuur September 2014 | Page 65

Typical Drosera aliciae individuals. they grow. With a few exceptions, their roots are very poorly developed consisting only of a few divided branches that are often referred to as ‘pseudo-roots’ (false roots) whose sole purpose is probably the absorption of water. The characteristic feature of sundews is their leaves, which are covered with sensitive, glandular red hairs or tentacles that are movable yet amazingly firm. The glands at the tips of the tentacles are all surrounded by large drops of extremely sticky, clear secretions that, glistening in the sun, have given rise to the plants' poetical name, ‘sundew’. Although the leaves do not appear green (because of the red tentacles), they do contain chlorophyll and are therefore able to photosynthesise and produce carbohydrate food. Whether insects alight on the leaves In Drosera aliciae old, dead leaves are retained, creating a mound. by mere chance as a resting place or are attracted by the odour of the glandular secretions, is not known. If the odour is attractive, the leaves may be compared to a baited trap. Whatever the mechanism, when an insect lands on a leaf, it is instantly entangled by the sticky secretions and the glands at the tips of the tentacles, excited by the repeated touches of the struggling insect, increase their secretions making the insect's escape virtually impossible. The surrounding tentacles then slowly bend toward the insect, engulfing it altogether. Alternatively, the leaf itself may fold to engulf the struggling insect. The glands release digestive enzymes that then dissolve the insect and its organic nutrients (especially valuable nitrogen), which are then absorbed through the leaves. Most sundews occur along permanent water seepages yet surprisingly, falling drops In D. capensis the inflorescence characteristically nods above the base of the single open flower. of water do not cause stimulation of the tentacles or the leaves. Of the sundews found in the Western Cape, four species are comparatively widespread. Drosera aliciae (shepherd's crook sundew, Alice sundew, sondouw) is a hardy, longlived sundew that is moundforming, characteristically retaining its old, dead leaves. The species produces a rosette (to 25 mm) of stalkless leaves that are spoonshaped. During their flowering period from November to January, a leafless stem up to 40 cm arises from the middle of the leaf rosette bearing up to twelve small (15-20 mm in diameter) pink to purple flowers. Drosera aliciae is common in damp, peaty, exposed habitats in mountainous areas. Due to its hardy nature, the species is often also found along sporadic seeps. Drosera capensis (Cape sundew, Due to vegetative propagation, D. capensis individuals are often found clumped together.