SEEDLINGS OF THE TRIBUS RANUNCULEAE DC AN D THE TRIBUS ADONIDEAE KUNTH (RANUNCULACEAE)

The morphology of seedlings of the genera Adonis, Callianthemum, Ranun culus, Ceratocephalus, Myosurus and Trautvetteria is investigated and discussed. There exists a main seedling type, representing a dicotylou s seedling with epigeal germination. The cotyledons are connected at t heir leaf bases, forming a short cotyledonary tube and protecting the plumule. Hypocotyl and primary root are well developed but soon become replaced by adventitious roots. In Ranunculus, sect. Ranuncella seedl ings are characterized by a long cotyledonary tube. In some species hy pogeal germination occurs. A possible adaptive value of this behaviour to mountain conditions is discussed. Similar seedlings occur in Calli anthemum and Adonis sect. Consiligo. R. ficaria and R. glacialis have monocotylous seedlings. Occasionally monocotylous seedlings could be f ound amongst the normal dicotylous seedlings in several other Ranuncul us species. The derivation of the monocotylous character state in R. f icaria and R. glacialis via neoteny due to the delayed development of the embryo under conditions of a short growing season is supposed.