Plant Systematics Questions and Answers

Answer: A

The division is not followed in the APG system.

The Angiosperm Phylogeny Group system is based on molecular phylogeny. It keeps the monocots as a natural group but finds the dicots paraphyletic, so it splits them into the basal angiosperms (such as water lilies), the magnoliids and the eudicots.

Bentham and Hooker's system divides the flowering plants into Dicotyledons and Monocotyledons, and Engler and Prantl and Takhtajan (with his Magnoliopsida and Liliopsida) also keep the two classes.

Answer: C

The two words designate the generic name and specific epithet.

Under the botanical code, the name of a species is a binomial: the genus name followed by a specific epithet, as in Mangifera indica. The second word alone (indica) is not a species name; only the combination of both is.

That is why 'generic name and species name' is the near miss: it treats the epithet as if it were the whole species name. Family names are not part of the binomial, and a varietal epithet belongs to an infraspecific name, which adds a third element.

Answer: D

The organ that does not belong to Pentoxylon is Williamsonia.

The Jurassic plant Pentoxylon sahnii, described by Birbal Sahni from the Rajmahal Hills, has been reconstructed from separately named fossil organs: Pentoxylon (stem), Nipaniophyllum (leaf), Carnoconites (female, seed-bearing cone) and Sahnia (male, pollen-bearing organ).

Williamsonia is a reproductive structure of the Bennettitales (cycadeoids), a different group of Mesozoic gymnosperms whose plant is reconstructed with leaves such as Ptilophyllum. The other three options are all parts of Pentoxylon.

Answer: C

The statement contrary to the rules is that biological names can be written in any language.

Under the international codes of nomenclature, scientific names are Latin or latinised, whatever their origin, so that one name is understood everywhere.

The other three are the rules themselves. In binomial nomenclature the first word is the genus and the second the specific epithet; names are printed in italics; and when handwritten, where italics are not possible, the genus and species names are underlined separately.

Answer: A

The first vascular plant fossils appear in the Silurian period.

The earliest known vascular plants, such as Cooksonia, are found in rocks of the middle Silurian, about 430 million years ago. They were small, leafless, branching stems with sporangia at the tips, and vascular plants then diversified rapidly in the Devonian.

The Cambrian is too early, with no land plants yet. The Triassic and Jurassic are Mesozoic periods, by which time ferns, conifers and cycads were long established.