NDA (I) 2018 General Ability Test · Question 72 of 150

Correct — D, Vascular system is not found among Bryophytes. Bryophytes are the mosses and liverworts, and they are the first group of the plant kingdom to come out on land while still tied to water. Their body is differentiated into something like a stem and leaves, but they have no xylem and no phloem — no specialised conducting tissue to carry water up or food down. Every cell must obtain water more or less directly, which is why bryophytes stay small, keep to damp shaded places, and need a film of water for fertilisation. Their nickname, the amphibians of the plant kingdom, records exactly that half-and-half position.

• (a)Thallophytes have well differentiated body design — The reverse is true, and the name itself says so. A thallus is a plant body not divided into root, stem and leaf, and thallophytes — the algae — are grouped together precisely because their body is not differentiated.
• (b)Funaria is a fungus — Funaria is a moss and therefore a bryophyte, not a fungus. It is the moss that school textbooks use as their standard example of the group, which is what makes this a tempting swap.
• (c)All Pteridophytes are Phanerogams — The two terms are opposites in this classification. Phanerogams are the seed-bearing plants — gymnosperms and angiosperms. Pteridophytes, the ferns and their relatives, reproduce by spores and bear no seeds at all, which places them among the cryptogams.

The traditional school classification of the plant kingdom runs in five groups of rising complexity. Thallophyta are the algae, with an undifferentiated thallus. Bryophyta are the mosses and liverworts, with a differentiated body but no vascular tissue. Pteridophyta are the ferns and horsetails, the first to possess xylem and phloem, and they still reproduce by spores. Gymnosperms bear naked seeds, and angiosperms bear seeds enclosed in a fruit. The first three together are the cryptogams, whose reproductive organs are hidden; the last two are the phanerogams, the seed plants.

Three of the four options here are built by breaking one line of that ladder, so the reliable approach is to place each named group on the ladder before judging the sentence. Thallophyta fails on body design, Pteridophyta fails on seeds, and Funaria fails on which group it belongs to. Two boundaries repay memorising because examiners return to them. The first is the vascular boundary, which falls between bryophytes and pteridophytes — pteridophytes are the earliest vascular plants. The second is the seed boundary, which falls between pteridophytes and gymnosperms and separates cryptogams from phanerogams. Fixing those two lines answers most items in this chapter, including the one a later NDA paper set on what is not true of bryophytes.

• Bryophytes have no xylem or phloem and so no vascular system.
• Bryophytes are called the amphibians of the plant kingdom because they live on land but need water for reproduction.
• Funaria is a moss and a standard textbook example of a bryophyte.
• Pteridophytes are the first vascular plants, and they bear spores rather than seeds.
• Cryptogams cover thallophytes, bryophytes and pteridophytes; phanerogams cover gymnosperms and angiosperms.

• Assuming a group with stem-like and leaf-like parts must also have conducting tissue.
• Placing a moss among the fungi because both grow in damp shaded places.
• Treating pteridophytes as seed plants because they are vascular.

NDA sets it as a four-statement screening item, or by asking which group is called the amphibians of the plant kingdom, or which is the first to be vascular.

• practice — not a real PYQ

  The first group of plants to possess a proper vascular system is

  • (a)Thallophyta
  • (b)Bryophyta
  • (c)Pteridophyta
  • (d)Gymnospermae

  Answer(c) Pteridophyta — ferns and their relatives are the earliest plants with xylem and phloem, though they still bear spores.

• practice — not a real PYQ

  Plants that bear naked seeds not enclosed in a fruit are called

  • (a)bryophytes
  • (b)pteridophytes
  • (c)gymnosperms
  • (d)angiosperms

  Answer(c) gymnosperms — the name itself means naked seed, and Pinus and Cycas are the standard examples.