Structural and ecological characteristics of tuberous Umbelliferae of Crimea

Among the 95 studied Crimean species of Umbelliferae, about 8% have hypocotyl tubers. Among them: hypocotyl-tuberous biennial and perennial monocarpics make up 3%, hypocotyl-tuberous polycarpics – 1%, radish-like hypocotyl-taproot-tuberous biennial and perennial monocarpics – 4% (this group is relatively numerous in Crimea due to representatives of the genera Trinia and Rumia). Metamorphosis of underground organs in hypocotyl-tuberous species occurs at the earliest stages of ontogenesis; usually, seedlings already have a tuber immersed deep in the soil, formed due to thickening of the hypocotyl, as well as a long cotyledon tube. The group of radish-like hypocotyl-taproot-tuberous monocarpics is very close to hypocotyl-tuberous biomorphs, however, the specialization of underground organs here occurs at later stages of ontogenesis, a well-developed main root is preserved until the end of life. Species with tubers of hypocotyl origin, noted in Crimea, are diverse in their morphology and demonstrate different directions of structural-ecological adaptation: in some plants to the life of a mountain forest ephemeroid (Smyrnium perfoliatum), in others – to grow in open areas in climate with a dry summer period (Bunium microcarpum, Elaeosticta lutea).