Who will introduce me to yam?

What is a yam? Who will introduce me to yam? Morphological characteristics the rhizome is thick, straight, up to 1 meter long. Leaves alternate, opposite above middle, rare or 3 whorled, often bulbous between leaf axils, leaf shape varied, triangular ovate to triangular broadly ovate, often 3-lobed to parted. Flowers dioecious, very small, green-white, all spikelike, male inflorescences erect, female inflorescences. The capsule has 3 wings. Perennial twining herbs; clumpy or rootlike underground stems; leaves alternate, sparsely opposite, simple or palmately compound, divided or divided; flowers dioecious; rarely the same plant, forming spikes, racemes or panicles; tepals 6 whorled in 2 whorls, basally connate; stamens 6, sometimes 3 developed, 3 degenerated; female and male flowers similar, but stamens degenerated or absent; ovary inferior, 8-loculed, styles 3, separated; capsules or berries. Seeds winged. The growth habit is light-loving, and the cold resistance is poor. It is suitable to grow in a well-drained, loose and fertile loam. Avoid waterlogging. The stem of underground yam is cylindrical, and it may also be deformed, fleshy and thick because of different growth geology. The first kind of yam: stem cylindrical, leaf blade triangular-ovate to triangular-broadly ovate, base hastate heart-shaped. Male inflorescences spikelike, not pendulous, long rachis mostly zigzag, male flowers subsessile, bracts triangular-ovate, shorter than perianth, tepals 6, ovate, stamens 6, developed; female inflorescences similar to male inflorescences, ovary stigmas 3-lobed. The capsule has 3 wings, the wing length is equal to the width, with a short stalk, 2 seeds per locule, inserted in the center; the seeds are ovoid, surrounded by chestnut shell thin wings, wings about 6 mm wide, unequal width around. The flowering period is from June to August and the fruiting period is from August to October. The second kind of yam: asexual reproduction, cylindrical stem, heart-shaped leaves, no flowers, "yam beans" between leaf axils, "yam beans" fell to the ground after stems and leaves withered in autumn and winter, and sprouted in spring the following year. Click to see more yam planting techniques click to see more vegetable planting techniques