Question

Which is nearest to Corymb?

Answer 1

Hint: The youngest flowers in indeterminate inflorescences are at the top of an elongated axis or in the centre of a truncated axis. A raceme, panicle, spike, catkin, corymb, umbel, spadix, or head is an indeterminate inflorescence.

Complete answer:
A flower appears in a raceme at the upper angle (axil) between the stem and branch of each leaf along a long, unbranched axis. Each flower is carried on a short stalk known as a pedicel. The snapdragon is an example of a raceme (Antirrhinum majus).

A panicle is a branched raceme with multiple flowers on each branch, such as the astilbe (Astilbe). A spike is a raceme, but the flowers grow directly from the stem rather than on pedicels like barley (Hordeum). A catkin (ornament) is a spike with either male (staminate) or female flowers (carpellate). It is usually pendulous, with a reduced or absent, as in oaks (Quercus).

A corymb is a raceme in which the pedicels of the lower flowers are longer than those of the upper flowers, resulting in a flat-topped inflorescence, similar to hawthorn (Crataegus).

Each pedicel in an umbel begins at roughly the same point at the tip of the peduncle, giving the appearance of an umbrella-like shape, as in wax flowers (Hoya). A spadix is a spike that grows on a fleshy stem and is common in the Araceae family (e.g., Philodendron). A spathe is a subtending bract.

A capitulum (short dense spike) is a short dense spike in which the flowers are borne directly on a broad, flat peduncle, giving the inflorescence the appearance of a single flower, as in dandelion (Taraxacum).

Thus, Umbel is nearest to corymb.

Note: A corymb has a flattish top with a superficial resemblance to an umbel and may have a panicle-like branching structure. Flowers in a corymb structure can be parallel or alternate, and they can be convex or flat. Many Maloideae species, including hawthorns and rowans, produce corymbs as their flowers. Corymbs can also be found in Norway's maple and yerba maté.