Notes on Distribution and Biology of Aponogeton ranunculiflorus

This unusual species of Aponogeton was described in I972 (A. Jacot Guillarmod & W. Marais in Kew Bull. 27: 563-565, 1972). As far as was then known the total area in which the plant occurred was 3 hectares and as it grows in rock pools, the actual habitat area was thus much less. Fortunately all the pools containing the plant were within the boundaries of the Sehlabathebe Mountain National Park, Lesotho, and thus well protected. Since then, Mr. P. Cookingham has explored on the Republic of South Africa side of the boundary fence, within about two kilometres of the nearest site in the park, and has found, at the same altitude and in the same type of situation, some pools in Cave Sandstone rock containing the plant. This places the species also in Natal, RSA. In 1976 Dr. F. Hoener, botanist at the park, reported a further find within the boundaries of the park, but at the southern extremity near the border with the Cape Province, RSA. The distribution is thus more widespread than at first thought, but all occurrences are at the same altitude of approximately 26oo m, in Cave Sandstone rock pools and within a Io km distance. Mr. Cookingham further observed that some of the pools may ice up completely during winter so that the plants are frozen into the muddy bottom. Also, at times, the pools may, if shallow, dry up but once filled again by rains and run-off water, the Aponogeton continues growth from the minute corms. The plant thus withstands very varied conditions and a great range of temperatures. In February, 1975, seed collected, with permission from the Park Manager, was sent to the Royal Botanic Gardens, Kew and also to Holland, while some seed and small corms were taken to Grahamstown. In the laboratory, the author has cultivated the plant since then under the following conditions. A glass fish tank capable of giving a depth of about 29 cm of water was filled to within 2 cm of the top with acidic borehole water. This water comes from a borehole in Witteberg quartzite rock and the pH value is within the