In this article we will discuss about the size of pollen and spore walls. Size: There exist much variations in sizes of pollen and spores. The size may be 5 µ × 2.4 µ as observed in pollen of forget-me-not (Myosotis) or as high as 200 µ or more as is noted in certain genera of Cucurbitaceae and Nyctaginaceae etc. [...]
Polarity is defined as the condition of having distinct poles in a pollen grain. Jackson in 1928 assumed that a pollen grain points to the poles like Silphium. Silphium laciniatum, also known as compass plant, has leaves that 'turn their edges north and south and avoid the mid-day radiation' —Willis. Pollen mother cell after meiosis forms four pollen grains that [...]
NPC is an artificial system of classification of pollen and spore based on the three features of aperture only, i.e. number, position and character. Erdtman and Straka (1961) proposed NPC classification and palynologists all over the world accepted it. According to NPC system each pollen grain has an arithmetic cardinal number consisting of three digits. The first digit reveals the [...]