A comparative study on the veinlet endings in 118 taxa ofHibbertia has been made. The vein-endings have been classified into three categories, namely conventional tracheids, tracheoids and sclereids. Typological features of the tracheoids and sclereids are found to be of exceptional interest in the provisional confirmation of a few taxa and also for understanding the taxonomy of this genus.

A resume on the morphological features of tracheoids has been presented under various typological heads with examples drawn from the published literature to enhance their utility in detailed descriptions of tracheoids. Depending on the constancy of cell form the tracheoids are classified under two groupings: homomorphic and heteromorphic. Homomorphic group includes brachytracheoids, sclerotracheoids, macrotracheoids, tubuliform spirotracheoids, vermiform tracheoids and loratotracheoids. Heteromorphic grouping includes heterotracheoids. Each type represents a descriptive unit recognised on the cell form and is supported by a qualifying description for their delimitation.

A topographic survey of the laminae ofGarrya has revealed that sclereids are present only in 14 taxa and they conform to polymorphic, groupings. The usefulness of sclereids in the provisional identification, nomenclatural changes and taxonomic status has been discussed.

The present work has revealed that 32 out of 38 taxa ofIsopogon possess variously shaped sclereids of diffuse pattern. Some species have grotesquely mis-shapen sclereids with thick wall and blunt arms. They are designated as gnarlyform sclereids. Further, the taxonomic problems alluded to by Bentham are discussed in relation to the types of foliar sclereids.

Foliar sclereids inLimonium Tour. exhibits diffuse, terminal or mixed patterns of distribution. A few instances have been focussed to place on record the importance of sclereids in any future taxonomic revision of this genus.

The present study has revealed that 24 out of 39 taxa ofPetrophile possess diverse types of sclereids. Further, it is observed that similar types of sclereids are present at the various sectional levels as recognised by Bentham. Their morphological aspects and systematic applicability have been discussed.