Question

Smallest parasitic flowering plant is
(a) Arceuthobium
(b) Rafflesia
(c) Balanophora
(d) Cistanche

Answer 1

Parasitic plants are the plants that derive some or all of their nutritional requirements from other living plants. They are present in all the biomes and can be of varying sizes. The smallest parasitic flowering plant is also known as the dwarf mistletoe and belongs to the family ‎Santalaceae.

Complete Step by Step Answer:
Arceuthobium , also known as the dwarf mistletoe, is a parasitic plant that grows on trees like pine, etc. It is about 5mm- 8mm in length and it is the smallest parasitic flowering plant known to date.
These plants have very reduced shoots and leaves that are mostly reduced to scales, with the bulk of the plant living under the bark of the host tree.
- These plants are dioecious, individual plants that are either male or female. The fruits of this plant are unusual as they build up hydrostatic pressure internally and when they are ripe, the fruits shoot out single sticky seed at very high speeds to disperse them.
- The interaction between the dwarf mistletoes and their hosts can be categorized as a source- to- sink relationship.
- They obtain the majority of the nutrition required from the host’s vascular system.
- Rafflesia is the largest parasitic angiosperm.
- Balanophora is a parasitic plant that measures about 30 mm in length.
- Cistanche is a holoparasite and it is about 20 to 100 mm in length.

So, the correct answer is, '(a)Arceuthobium '.

Note:
- Arceuthobium has a root- like endophytic system, that is composed of primary and secondary haustoria. They invade but do not injure, the vascular elements, both the xylem and the phloem of the host.
- Since, this root- like endophytic system is not soilborne, these plants are dependent entirely on their host for water.
- However for seed dispersal their fruits use a hygroscopic substance viscin which swells by absorption of moisture from the atmosphere and then disperses the seed.