The present investigations were conducted on two important nectar and pollen yielding plants viz. Plecranthus coesta and Plecranthus rugosus from different agro-climatic zones of Himachal Pradesh. The bee forage plants were collected, identified, classified and diffentiating characters of two species were noted. Apart from this, pollen grains of P. coesta and P. rugosus were also studied using light and scanning electron microscope. The pollen grains were observed in terms of aggregation,

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... shape class, size, aperture, polarity, symmetry, surface pattern/exine complexity. Both P. coesta and P. rugosus had solitary medium sized, hexacolpate, isopolar and radially symmetric grains. However, the pollen grain of two species varies in shape and exine complexity. P. coesta pollens were round/ circular and were prolate, whereas in P. rugosus pollens were round/oval and subprolate-prolate. Variation was also found in the exine complexity of the two species. Exine was tectate, tectum was nearly reticulate / scabrate in P. coesta. But in P. rugosus and exine was either tectate or semitectate, tectum was reticulate, microreticulate.