Question

Deacribe the theories of "original of angosperms"

Answer 1

According to Campbell (1928) the herbaceous angiosperms are primi­tive, those inherited from filicinean ancestor. He also pointed out that the Isoetes, a living heterosporous genus, shows possible relationship with monocotyledons. Like most of the members of Filicineae, the Isoetes grows in aquatic or amphibious environment indicating relationship with monocotyledons.

Campbell suggested that though Isoetes shows similarity with mono­cotyledons like Najas flexilis with regard to habitat, anatomy of old sporophyte and resem­blances in embryo, the differences in respect of simplest angiosperm flower and sporophylls of Isoetes need more evidence to support the hypothesis.

The Lycopodiales and Equisetales are now considered as completely separate and indepen­dent evolutionary lines.

The monocots are now considered to be more advanced than dicotyledons and their resemblance with Isoetes is superficial in nature.

Answer 2

Angiosperms are the plants in which seeds are enclosed into a fruit.

Kingdom plantae is divided into two groups :

1. Cryptogame ( cryptos: hidden,gamos: marriage)

2.phanerogames ( phanero: visible,gamos: marriage)

Phanerogame is divided into two subgroups on the basis of position of seed i.e. angiosperms and gymnosperms

Angiosperms is again divided into monocots and dicots

Hope it helps