Question

A student observed a plant with stellate hairs on vegetative parts and fruits dehiscing into many seeded mericarps, which one of the following characters is associated with that plant?
a. Failure of the germination of pollen grains on the stigma of the same flower
b. Presence of monosiphonous pollen grain
c. 3-10 bracteoles forming a whorl on the calyx
d. Two carpels in the gynoecium of a flower

Answer 1

Hint: A genus of plants that are all native to mainland Australia within the figwort family. Generally, they are used in funeral ceremonies and in ceremonies of initiation.

Complete answer:
> Option A is correct. The plant with stellate hairs on vegetative sections belongs to the Eremophila group, there is floral form variation, the most common being two petals at the top of the tube and three below, with the stamens in the tube enclosed. Species with this arrangement tend to self-pollinate and are normally pollinated by insects.

> Option B is incorrect. Pollen-grain forms the pollen tube during germination. The pollen grain normally produces only one tube of pollen, namely a monosiphonous. For instance, Poaceae in Zea mays. Nearly all pollen grains are monosiphonous, i.e. each pollen grain contains only one tube of pollen. Other pollen, such as that of some Malvaceae, Cucurbitaceae and Campanulaceae family members, are polysiphonous, each grain emitting more than one pollen tube (polysiphonic pollen function).

> Option C is incorrect. An epicalyx forming an additional whorl around a single floral calyx is a bracteole modification. In other words, the epicalyx is a group of bracts which resemble a calyx or bracteoles forming an outer whorl to the calyx. It is an extra whorl of floral appendages, like a calyx. Specific epicalyx section is called an episepal, since it resembles the sepals in it. They are found in Malvaceae, the family of hibiscus. Fragaria (strawberries) may have an epicalyx, or not.

> Option D is incorrect. A pistil may consist of one carpel with its ovary, style and stigma, or multiple carpels may be joined together with one single ovary, the whole unit being called a pistil. Gynoecium can constitute about one or maybe more pistils of uni-carpellate (with one carpel), or pistils of multi-carpellate.

Hence, The correct answer is option (A).

Note: Eremophila comprises entomophilous species, with flowers designed to attract insects, and ornithophilous species, with bird-attracting flowers. In addition, bird pollinated species tend to have longer stamens that brush pollen on and off the bird's head as it feeds.