Coriander, Coriandrum sativum L.

It is easy to define nectaries from a functional point of view: they are plantsecreting structures that produce nectar, but it is difficult to provide a general definition. From the anatomical point of view nectaries vary widely in ontogeny, morphology, and structure (Fahn, 1979a, 1988; Durkee, 1983; Smets et al., 2000), both between species and within species, depending on flower sexual expression or flower morph in heterostylous and heteroantheric species (Nepi at al., 1996; Küchmeister et al., 1997; Fahn & Shimony, 2001; Pacini et al., 2003). Intraspecific morphological differences exist between flowers of the same plant and between plants of the same species with different ploidy (Davis et al., 1996), and morphological characters may be

Nectary structure and ultrastructure

The construction of classifications, as well as the understanding of biological diversity, depends upon a careful comparison of attributes of the organisms studied (Stuessy, 1990). It is widely known that data from diverse sources showing differences from taxon to taxon are of systematic significance. During the 20th century, systematists have emphasized that their discipline involves a synthesis of all knowledge (Stevens, 1994) or, in other words, the variation of as many relevant characters as possible should be incorporated into the natural system to be constructed. The extent to which particular characters are constant or labile will determine their usefulness to systematics. In general, more conservative characters will be valuable in defining families and orders, whereas more labile characters may be useful at the generic and specific levels (Webb, 1984). There is no doubt that floral characters are among the most used in the classification of flowering plants. At the same time, they constitute essential features in diagnostic keys to taxa in both taxonomic treatments and Floras (Cronquist, 1981, 1988).

A systematic survey of floral nectaries

Cladistics and family level classification of the gentianales

The diversity, ecology and evolution of extrafloral nectaries: current perspectives and future challenges.

Structural, functional and phylogenetic aspects of the colleter

Histochemistry and senescence of colleters of Allamanda cathartica (Apocynaceae)

The colleters of Roupelia grata are present on the petiole of the leaf, bract, bracteole and calyx. A mature colleter has a distinct head and a stalk. The parenchymatous central core is surrounded by epithelial cells. The senescence of the colleter occurs at its apex first and then proceeds towards the base.

Vinoth Thomas

Papers

Structural, functional and phylogenetic aspects of the colleter

Histochemistry and senescence of colleters of Allamanda cathartica (Apocynaceae)

Anatomy and histochemistry of colleters in Roupelia grata (Apocynaceae)

Structure and biology of nectaries in Tabebuia serratifolia Nichols (Bignoniaceae)

Anatomical and Histochemical Aspects of Bark Regeneration in Hevea brasiliensis