К ОПРЕДЕЛЕНИЮ ОРХИДЕЙ (ORCHIDACEAE) СОЧИНСКОГО ПРИЧЕРНОМОРЬЯ ПО МИКРОМОРФОЛОГИЧЕСКИМ ПРИЗНАКАМ СЕМЯН

Abstract

According to the results of preliminary studies of the micromorphology of orchids seeds in the Sochi Black Sea region, a key has been compiled to identify 25 species and subspecies from 13 genera by seed. The most valuable features of seed structure for diagnosis were identified from the previously described characteristics: seed shape, its length, the number of cells in testa, their shape in different parts of testa. Limodorum-type seeds have fusiform, linear or balloon-shape and Orchis-type seeds are pear-shaped or club-shaped. The shape of the cells is the same throughout the testa or contrasting one – elongated in the micropylar and medial parts and isodiametric at the chalazal pole. This trait also distinguishes the type of seed. Some genera are characterized by convoluted or smooth anticlinal cell walls. The periclinal walls of the cells have sculptural thickenings of different patterns, or no pattern. This feature consistently characterizes different genera and even species. Frequent or rare stripes of the sculpture, mostly straight or curved, forming gaps at the borders of cells or not – these features are species-specific. Relative sizes, in particular, the ratio of the length of a seed to the length of an embryo, as well as the proportion of sizes of parts of seed coats have great specificity. On the contrary, orientation of the strokes of the sculpture, the presence of suspension residues and the degree of homogeneity of an embryo are not reliable diagnostic features. The key is useful for field researches for studying the distribution of orchids in the period after flowering and until the seeds are completely dispersed.