Nasti'Rtium, the generic name of a plant of the cruciferoe or mustard family, and the common name of the widely different genus tropoeolum. The genus nasturtium (Lat. nasus tortus, a tortured nose, some of the plants being exceedingly pungent) includes among other plants the well known water cress and horse radish, both of which are described under their proper titles. The old herbalists, who classified plants by their sensible properties rather than by their structure, finding the species of tropceolum to possess a pungency similar to that of the cruciferous plants, included them under nasturtium, a name which in this or its altered form of sturtion they have retained, in spite of the fact that the books give Indian cress as their suitable common name. In the most recent revision of genera tropaolum (Gr. s trophy, the leaves of some resembling a shield, and the flowers a helmet) is placed in the geraniaceoe; it includes tender South American herbs, most of which climb by means of their long leaf stalks, and have a pungent watery juice with the taste and odor of cress. There are about 35 species, most of which are in cultivation, besides numerous garden varieties. Some are treated as garden annuals, others as greenhouse plants; a number of the species produce tubers.
The flowers consist of five sepals, united at the base and extended at the upper side of the flower into a long spur; petals live or fewer, usually with (daws, the upper two somewhat different from the others and inserted at the mouth of the spur; stamens eight, unequal; ovary three-lobed with a single style, and in fruit forming three fleshy separate carpels. The common garden nasturtium (T. majvs) is one of the most generally cultivated annuals; the stem climbs 6 or 8 ft,, and is often planted near fences, or provided with brush, which it soon covers with its peltate foliage; the flowers vary from yellow to orange, scarlet, and crimson; the three lower petals have longer claws than the others, and are fringed at the base. There is a double variety, and dwarf forms which do not climb. The unexpanded flower buds, and the young fruit while still tender, are pickled in vinegar; and the French, who call the plant capucine, use the gay-colored flowers to ornament salads. The dwarf varieties of this form bushy rounded tufts about a foot high, and are used for bedding; some of the named varieties have flowers of exceedingly rich colors.
The smaller nasturtium (T. minus) has smaller flowers, with petals pointed at the tip, and smaller seeds; but it is so mixed up with the dwarf forms of the preceding that the true species is rarely met with. The canary-bird flower (T. peregrinum) is one of the most interesting of garden climbers, and very unlike the others; it climbs high and spreads rapidly; its leaves are five- to seven-lobed, and its small flowers have the two upper petals cut-lobed, the lower ones fringed, and the spur curiously curved; when partly expanded the flowers may be fancied to resemble a little bird, an appearance which is aided by the lively canary-yellow color of the petals. It is an easily cultivated annual, which like the others is more productive of flowers in rather poor than in rich soils. The tuberous nasturtium (T. tuberosum) has red and yellow tubers the size of a small pear, five-lobed leaves, short orange-colored petals, and an orange-red calyx with a heavy spur. This is the ysano of the Peruvians, with whom it is held in high esteem as an article of food; and it has been introduced into Europe and this country as a garden vegetable, but has met with little favor. In South America the tuber is first boiled and afterward frozen, and is eaten in the frozen state.
The tubers are preserved and propagated in the same manner as potatoes. Lobb's nasturtium (T. Lobbianum) is a favorite greenhouse climber, but it does not flourish so well in the open air as the common species, which it much resembles; it has smaller and slightly hairy leaves, and much fringed flowers, which in the many named varieties present a great diversity of color. Among the tuberous-rooted greenhouse species are T. tricolorum, with scarlet and black flowers; T. azureum, blue and white; and T. Jarattii, carmine and yellow. They are summer-flowering, and remarkable for the exceeding delicacy of their stems, which near the tuber are scarcely larger than a thread; they are trained upon low trellises, while T. penta-phyllum, also tuberous, can be trained to pillars and rafters. All the tropaeolums are raised from seed, which in some is very slow in germinating, and those with fleshy stems grow readily from cuttings.
Dwarf Nasturtium (Tropa?olum minus).
Canary-Bird Flower (Tropaeolum peregrinum).