Andromonoecy, flowering and pollination biology of <I>Dorema microcarpum</I> (Apiaceae) in the conditions of the Ferghana Valley (Uzbekistan)

Andromonoecy was described and anthecological features were identified for the first time in Dorema microcarpum, a perennial monocarpic plant endemic to the Western Tien Shan and Northern Pamir-Alai. The research was carried out in the natural conditions of the Chust-Pap adyrs of the Fergana Valley in 2021–2023. The floral unit is shown to be an open tiered raceme of tiered racemes of simple umbels. In powerfully developed plants, paracladia are formed in the lower part of the synflorescence. The duration of flowering of an individual is 10–15 days. Simple umbels in different parts of the synflorescence can form only perfect flowers, or perfect and staminate flowers, or only staminate flowers. In poorly developed plants, simple umbels of lateral racemes from the 6th node form perfect flowers and 1 to 5 staminate flowers; simple umbels of 2–3 lower lateral racemes form only staminate flowers. In powerfully developed plants in the middle and upper parts of synflorescence, almost all simple umbels form only perfect flowers; staminate flowers are observed only on paracladia. The flowering of an individual begins with simple umbels on the lateral racemes located in the middle floral unit, namely from the 6th to the 9th nodes and occurs divergently: first, the middle and upper parts of the synflorescence completely fade, then the staminate flowers open on the lateral racemes of the lower parts (from the 3rd to the 5th nodes). The opening of flowers on lateral racemes occurs acropetally, and within simple umbels centripetally. D. microcarpum is a plant with a morning flowering rhythm: the opening of flowers begins early in the morning (about 5–6 a. m.) and continues until 9–10 a. m. Perfect flowers are characterized by strictly pronounced protandry. The flowering time of a perfect flower is 3–4 days, of a staminate flower – 1 day. The flowers are mainly visited by insects of two orders, Hymenoptera and Diptera. The presence of both perfect and staminate flowers, different times of their maturation and a strict synchrony of flowering of the perfect flowers of upper lateral racemes contribute to geitonogamy and also ensure cross-pollination of other individuals. Staminate flowers of lower lateral racemes or paracladia provide cross-pollination between individuals in different flowering phases.