Question

Inflorescence is thyrse / thyrsus in _____
A. lantana
B. grape
C. Jasminum
D. Echinops

Answer 1

Thyrse is a mixed type of inflorescence which is generally by mixing of racemose type and cymose type. So, we have to think about the example and structural representation of inflorescence.

Complete answer:
In general, the inflorescence is represented as the structural representation of the flower in the axis of the plant. They are two types i.e.
I- racemose/indefinite type
II- cymose/ definite type
III- thyrse / mixed type

The example of mixed type of inflorescence in which the main axis grows indeterminately but the sub axes have determinate growth. It has two types;
-Mixed spadix- banana
-Cymose raceme- grape

Hence, the correct answer is option (B).

Additional information:
RACEMOSE/INDEFINITE -In this type of inflorescence the main axis continues to grow and does not terminate in a flower and flowers are borne laterally in an acropetal order /acropetal succession (Where old flowers are arranged at the lower side and young flowers are at the upper side.
This is of following types:
Raceme - In this type of inflorescence, peduncle (main axis or floral axis) is elongated and flowers are pedicellate. Eg. Radish, mustard
When peduncle is branched and each branch bears pedicellate flowers like raceme and are arranged in an acropetal manner then it is known as compound raceme or Raceme of racemes or panicle. Eg. Gulmohar, Cassia.
Spike- In this type of inflorescence peduncle is elongated but flowers are sessile (without pedicel). Eg. Achyranthes.
WhenWhen peduncle is branched and each branch bears spike-like inflorescence then the small branch having flowers is called spikelet and this arrangement is called spike of spikelet. E.g. Grass family (Gramineae = Poaceae).
Note: The grape is the only example of the thyrse inflorescences. The thyrse inflorescences involve indeterminate growth of the main axis whereas the branches tend to show determinate growth.