Question

Match the following series.

	Series I		Series II
A.	Opuntia	D.	Stem thorns
B.	Asparagus	E.	Phylloclades
C.	Citrus	F.	Citrus

The correct pairing is

• A. AD, BE, CF
• B. AE, BF, CD
• C. AF, BE, CD
• D. AE, BD, CF

Answer 1

Answer: (B)

Stem thorn shown by Citrus, phylloclades by Opuntia and cladodes by Asparagus are all aerial modification of stem. When the stem becomes photosynthetic and modifies into green fleshy leaf like structure, having distinct nodes and intemodes leaves being reduced to spines, the structure is called phylloclade. Cladode is similar to phylloclade but only one intemode long. Stem is modified into stiff, pointed unbranched structures, in Citrus called thorns.