Rheum maximowiczii

Description

Rheum maximowiczii is a large herbaceous perennial plant species in the genus Rheum (rhubarbs) from the mountains of Central Asia where it grows in Kazakhstan, eastern Uzbekistan, Tajikistan, Kyrgyzstan and northeastern Afghanistan. It has a single, reddish, leafless, branched stem 40–100 cm tall, the base of which is compressed to (only) one side and is sulcate and is covered in minute warts or smooth. The lateral branches open to less than 45° to form a pyramidal-shaped inflorescence. The leaves are round, 50 cm long and 60 cm wide, and have a reniform base. The margin is slightly wavy and fringed in tiny needles. Each leaf has three extremely prominent veins which are lateral at the base and only fork towards the margin. The top of the leaf is smooth; the underside is warty along the veins. The petiole is short, shorter than half of the leaf blade, the top being warty, rarely glabrous (smooth). The flowers are congregated and have a long peduncle which is jointed at the base. The greenish tepals are subequal, around 3mm long and 1mm wide. The stamens are very long. The large, oval fruit are 20mm long and 15mm wide, and have lateral, cordate wings -dark reddish-black when ripe, red when immature, with a vein running near the edge. The tepals hug the fruit. The seed is ovoid, wrinkled and brown. It is primarily found in the Pamir, Altai and Western Tian-Shan mountains. It is found in Kazakhstan, eastern Uzbekistan, Tajikistan, Kyrgyzstan and northeastern Afghanistan. It grows in the Chimgan mountains in Uzbekistan, Chatkalsky Gorge in an offshoot of the Western Tian-Shan near Tashkent, the Chatkal Range straddling Uzbekistan and Kyrgyzstan, as well as the Zarafshan Range straddling Uzbekistan and Tajikistan. It also has been found growing in the Hissar Range and in the land around the Vakhsh River in Tajikistan. In Kyrgyzstan it grows in the Chuy region and Taldy-Bulak valley in the Talas Alatau, Talas Region. In Kazakhstan it is found growing in the Kaskasu Gorge in the Karzhantau range, Korday Pass, the Kuyuk Pass near Taraz, in a number of places in the Aksu-Zhabagly Nature Reserve, on the Zhetysu ridge in the Ala-tau, and in the Karatau Mountains. It has been collected growing from approximately 1700 to 3200m in elevation in the Western Tian-Shan, from in the 1300 to 2000m in the Chatkalsky, from 2300 to 2600m in the Zarafshan Range, 1780m in the Hissar, and 3300 to 3700m in the Vakhsh region.