Their cultural requirements are very similar to those of Vallota, flower production appearing to be increased as the bulbs fill and begin to outgrow the pot allotted to them. A small group of bulbous plants have developed a climbing habit as an adaptation to their particular environment in the wild and among them are several beautiful, easily grown plants mainly for greenhouse culture. The swollen tuberous rootstocks produced by several species of Tropaeolum bring them into my definition of bulbous plants and two of these, Г. tricolorum and T. tuberosum, are extremely attractive as well as easy to grow. Г. tricolorum from Bolivia and Chile begins its growth in the autumn sending up its slender, fresh green shoots in October. As the shoots appear they require the support of a network of slender twigs, i8in(45cm) or so high, over which they scramble before producing their delightful scarlet, black-tipped blooms. The tubers are best planted in a slightly acid, well-drained compost in deep pots or in the greenhouse border and provided frost is just excluded the plants will flower abundantly for several weeks during late winter and early spring. The orange-flowered T. tuberosum, also South American, blooms during the summer and autumn out of doors if the dormant tubers are planted 9 to i2in(23 to 30cm) deep in the early spring so that they do not suffer from frost damage. Recent introductions appear to be summer-flowering and hardier than the usual nursery stocks available which also tend not to flower until early autumn. Grown in a greenhouse border Г. tuberosum will reach ioft(3m) or more in height and flower for much of the winter, but if grown outside in the garden it is as well to harvest a few of the tubers and store them in dry, cool, frost-free conditions over winter. The tubers, like those of potatoes, are edible and close to the soil surface so may be killed in severe weather. Three genera of the lily family from Africa also provide us with climbers for the cool greenhouse. Gloriosa is a genus represented in tropical and subtropical Africa (and India) by a number of variations on a similar theme of red and yellow. A number of species has been described but botanists nowadays tend to regard these as forms of one very variable species, Gloriosa superba. In its "typical" form it has deep orange-red or yellow,nodding flowers several inches across and climbs to a height of 3 to 4ft(i to 1.25m) by means of leaf tendrils. Equally vigorous is the beautiful G. rothschildiana with bright red, yellow-based blooms with undulate margins. Sandersonia aurantiaca from South Africa (the only species of its genus) has finger-like tubers that produce scrambling stems and tendril-tipped leaves much like those of Gloriosa. It grows to about 3ft(im) in height and bears singly, in the upper leaf axils, pendulous, bright orange flowers about iin(2.5cm) across and shaped like the old-fashioned, waisted gas lamp mantle of the Victorian era.