Plant Kingdom

Psilophytes are the oldest of seedless vascular plants. The plants are characterized by absence of roots and presence of rhizoids, e.g., Rhynia is The most primitive member of pteridophytes-Lycopodium and Selaginella are developed pteridophytes in which plant body is differentiated into roots, stems and leaves.

Answer (d) Seed of Pinus gerardiana

Sphagnum is used as a fuel and has a good capacity of water absorption

Answer (a) Ephedra

In bryophytes the archegonia are flask shaped with clearly defined venter ? neck. After fertilisation the wall of venter which encloses venter canal cell & a large naked egg, forms calyptra. Calyptra provides a protective covering to the developing sporophyte.

Answer (b) Pteridophyta

Microsporophylls and megasporophyIls are the leaf-like structures on which microsporangia (pollensacs) and megasporangia are borne on the same plant of pinus. The sporophylls are aggregated in form of cones. Male cones are smaller, also known as microstrobili (staminate strobili). Female cones are larger, known at megastrobili (ovulate strobili). Each male cone consists of an elongated axis, bearing a number of spirally erranged microsporophyll. On the underside of which two microsporangia develop and get filled with microspores (pollen grains). Anther or microsporangium are the male reproductive structures of angiosperms. Microsporangium bears microspores (pollens), through microsporogenesis. The flowers of angiosperms are different in structure to the male and female cones and the sporophylls in gymnosperms. Ligule is a tongue like membranous Outgrowth, present on upper surface, near the base of the microphyllous leaf in pteridophyies (e.g., Selaginella). The ligule shrinks and becomes inconspicuous in mature leaves.

Cephaleuros virescens grows as a parasite on the leaves of tea and causes red rust of tea. It is the common intercellular parasitic algae of chlorophyceae.

Two types of roots are present in Cycas. Normal root Coralloid root: These roots develop from normal roots. Some lateral roots are ageotrophic or apogeorropic, dichotomously branched and look like corals and called as coralloid roots. These roots have algal zone of some blue-green algae as Anobaena, symbiotically in cortex. Coralloid roots are absent in Pinus, mosses and Sefoginefia.

Pollination in Cycas is anemophilous and takes place at celled stage (prothallial cell, generative cell, tube cell).

Answer (a) They require a layer of water for reproduction