Histology of medicinal plants

by William James Mansfield

In clover flowers the pollen grains are mostly rounded in outline, the wall is uniformly thickened, and cell contents are coarsely granular.

In belladonna flowers the pollen grains terminate in three blunt points.

In Spanish saffron the pollen grains are spherical and the cell contents are granular.

PLATE 113
Smooth-walled Pollen Grains

1. Cloves (Eugenia caryophyllata, Thunb.). 2. Santonica (Artemisia pauciflora, Weber). 3. Elder (Sambucus canadensis, L.). 4. Century minor (Erythræa centaurium [L.], Pers.). 5. Pichi (Fabiana imbricata, R. and P.). 6. Cyani. 7. Lavender (Lavandula officinalis, Chaix.). 8. Clover (Trifolium pratense, L.). 9. Belladonna (Atropa belladonna, L.). 10. Spanish saffron (Crocus sativus, L.).

PLATE 114
Spiny Walled Pollen Grains

1. Anthemis (Anthemis nobilis, L.).
2. Arnica (Arnica montana, L.).
3. Calendula (Calendula officinalis, L.).
4. Cassia flowers.
5. American saffron (Carthamus tinctorius, L.).
6. Blue malva flowers (Malva sylvestris, L.).

The non-spiny-walled pollen grains differ not only in microscopic appearance, but also in size. Clove pollen grains are the smallest, while Spanish saffron pollen grains are the largest.