What kind of phyllotaxy was examined in the Guava plant?

Correct — D. In guava a pair of leaves arises at each node, the two sitting across the stem from each other. That arrangement is opposite phyllotaxy.

Phyllotaxy is classified by how many leaves come off a single node: one leaf per node is alternate, two facing leaves per node is opposite, more than two in a ring is whorled.

Guava is the standard textbook example of the two-per-node case, alongside Calotropis: option (d).

Why the others are wrong

• (a)
  Superimposed — Superimposed is not a recognised type of phyllotaxy. The classification runs alternate, opposite and whorled, and this term is outside it.
• (b)
  Whorled — Whorled phyllotaxy puts more than two leaves at one node, forming a ring, as in Alstonia. Guava carries two leaves per node, not a whorl.
• (c)
  Alternate — Alternate phyllotaxy has a single leaf at each node, as in china rose, mustard and sunflower. Guava's leaves come in facing pairs, so this does not fit.

Phyllotaxy is the pattern in which leaves are arranged on the stem or branch, and it is decided at the node.

Alternate: one leaf per node, as in china rose, mustard and sunflower. Opposite: two leaves per node facing each other, as in Calotropis and guava. Whorled: more than two leaves at a node forming a ring, as in Alstonia.

Learn the type with its example plant. SSC asks the pairing in both directions, giving the plant and wanting the type, or giving the type and wanting the plant.

Key facts

• Phyllotaxy is the arrangement of leaves on the stem or branch of a plant.
• Guava and Calotropis show opposite phyllotaxy, a pair of leaves at each node.
• China rose, mustard and sunflower show alternate phyllotaxy, one leaf per node.
• Alstonia shows whorled phyllotaxy, more than two leaves at a node.

Common traps

• Confusing phyllotaxy, the arrangement of leaves, with venation, the pattern of veins.
• Accepting 'superimposed' as a real category because it sounds technical.

No directly related past PYQ was found.