1. what the difference between simple tunicated bulb and compound tunicated bulb (underground modification of stem) ?
2.what the difference between procombent and decumbent trailers ( subaerial modification of stem ) ?
Onion is an example of a simple tunicated bulb, in this fleshy scales on the outer region represent the leaf base and scale leaves in the inner region, The whole bulb is covered by a scaly tunic.
Garlic is an example of a compound tunicated bulb. In this each fleashy scale is covered by an individual tunic and the fleashy buds are called cloves or bulblets. These bulblets are covered by overlapping tunic.
Procumbent teailers completely lie on the ground because they are weak and cannot support the weight of the plant. E.g. Oxalis.
Decumbent trailers are those that trail for some distance and then rise at the apex to bear an apical bud. E.g. Tridax
Hope this helps,