Comparative Floral Morphology and Anatomy of Gagea s. str. and Lloydia

Abstract

Flowers of the five species from the four sections of the genus Gagea (that is, G. lutea , G. pusilla , G. reticulata , G. fragifera , and G. serotina (syn. Lloydia serotina ) were investigated by light microscopy. All investigated species had similar flower organization, vertical zonality of the gynoecium, and floral vascularization. In all species, the flowers were trimerous, with the superior ovary and short complete or semicomplete syntepalous zone at the base. The presence of the syntepalous zone allows consideration of such flowers as an intermediate between hypogynous and perigynous. All investigated species had nectaries at the base of the tepals. However, in Gagea s. str., they were represented by relatively small nectariferous areas of the tepals located at the beginning of the synascidiate zone of the gynoecium. In contrast, the nectaries in G. serotina were represented by elongated tepalar outgrowths located higher, at the level of the fertile symplicate zone of the gynoecium. Considering reports on the potential peltate origin of the nectaries in G. serotina , it is probably incorrect to interpret them as homologous to the nectaries in Gagea s. str. The gynoecium in the studied species demonstrated identical vertical zonality with synascidiate, symplicate, and asymptomatic zones, and corresponded to type C of the syncarpous gynoecium. At the base of the ovary, three carpels were congenitally isolated (primary synascidiate zone); however, they were isolated only postgenitally (secondary synascidiate zone). This secondary synascidiate zone originated from a symplicate zone due to the fusion of the carpelar margins. Although it looks like a synascidiate zone, for correct interpretation of the gynoecium’s vertical structure, it should be considered symplicate. The vascularization of the flower in all investigated species was similar, with the participation of lateral vascular bundles in the supply of placentas.