Introduction of the Plant Front Cover: Rheum nobile

RheumnobileJ. D. Hooker et Thomson, also named Gaoshan Da Huang, belongs to a member of the genusRheumfrom the family Polygonaceae.

The plants are perennial herbs, having stout roots and rhizomes which can be used as medicine. The stems are simple, erect, 1-2 m tall, with numerous basal leaves, stem leaves and leaf-like bractes. The basal leaves are rosulate, orbicular, ovate, or cordate-ovate, 20-30 cm in diam. The stem leaves and leaflike bracts are smaller upward, suborbicular, 5-13 cm in diam. The bracts are yellowish, covered with each other to form an airtight and translucent tower shaped greenhouse to resist high altitude, low temperature, strong wind and strong ultraviolet rays, and protect the axillary inflorescences inside the bracts.

Rheumnobileneeds as much as 15-45 years of vegetative growth to accumulates enough nutrients until it matures. It blossoms once a lifetime, then the plant dies as the fruit matures with the final nutrients distributed to the seeds. Flowering from June to July; fruiting in September.

Rheumnobileis an endemic Himalayan species, growing on alpine scree slopes and meadows at elevations of 4 000-4 800 m above sea level. It belongs to a group that has evolved and specialized with the rise of the Qinghai-Tibet Plateau and to adapt to the special environment of high mountains. Because of its extremely harsh growth environment, and long vegetative growth and phenological period,R.nobileis awfully rare.