Find the wrong pair.

Question

UnlockIAS · Accepted Answer

Correct — option (3). Read the stem twice before doing anything else, because this is a negative question: 'Find the wrong pair' asks for the item that fails, so the three pairs you can vouch for must be set aside and the one that does not hold is the answer. Nothing in the printing marks the word 'wrong' out. Note also what this question is not — it is not a two-column matching item. Each of the four numbered options is already a complete pair of botanical family names joined by a dash, and the task is only to judge each printed pair as it stands. What the pairs are doing is placing an old descriptive family name beside its modern equivalent. Botanical nomenclature standardised family names on the pattern of a type genus plus the ending -aceae, but eight long-established names that do not follow that pattern were in such general use that the International Code of Nomenclature expressly permits them to continue as alternatives. Those eight equivalences are Palmae and Arecaceae, Gramineae and Poaceae, Cruciferae and Brassicaceae, Leguminosae and Fabaceae, Guttiferae and Clusiaceae, Umbelliferae and Apiaceae, Compositae and Asteraceae, and Labiatae and Lamiaceae — a closed list of exactly eight, which is what makes it examinable. Checking the options against it, option (1) Labiatae–Lamiaceae is right, option (2) Palmae–Arecaceae is right, and option (4) Umbelliferae–Apiaceae is right. Option (3) pairs Compositae with Clusiaceae, and both halves belong to the list but not to each other. Compositae, the family of the sunflower, the marigold and the safflower, named for the composite flower head in which many small florets sit together on a common receptacle, is equivalent to Asteraceae, the name built from the genus Aster. Clusiaceae, built from the genus Clusia, is the modern name not of Compositae but of Guttiferae, a quite different family which includes Garcinia and to which kokum belongs. The pair as printed therefore joins the old name of one family to the new name of another, and it is the wrong pair the question is asking for. Option (3) is the answer.

Why the other options are wrong — (a) This pair is correct, so it cannot be the answer to a question that asks for the wrong pair. Labiatae and Lamiaceae are two names for the same family, the mint family, and each name is formed on a different principle. Labiatae is the older descriptive name and refers to the lipped, two-lobed corolla characteristic of the family, from the Latin for lip; Lamiaceae is the standardised name built from the type genus Lamium. The family includes mint, tulsi, lavender, sage and rosemary, and its members are widely recognised by their square stems and aromatic leaves. Both names remain valid and either may be used, which is precisely the point the question is testing — that these are alternatives for one family and not the names of two families.  (b) This pair is correct and is not the answer. Palmae and Arecaceae are two names for the palm family, Palmae being the old descriptive name and Arecaceae the standardised form built from the genus Areca, which gives the areca nut. The family includes the coconut, the date palm, the oil palm and the palmyra, and is of substantial economic importance in the coastal districts of Maharashtra as elsewhere along the Indian coast. As with the other three pairs on the page, both names refer to the same family and both are permitted under the international code; the pair would only fail if one of the two names belonged to some other family, which is exactly the defect in option (3).  (d) This pair is correct and is not the answer. Umbelliferae and Apiaceae name the same family, the one that includes coriander, cumin, fennel, carrot, celery and asafoetida. Umbelliferae is the descriptive name and refers to the umbel, the inflorescence in which the flower stalks all arise from a single point and spread like the ribs of an umbrella; Apiaceae is the standardised name built from the genus Apium, the celery genus. This pair is worth learning together with option (3), because both old names describe an inflorescence — the umbel in one case and the composite head in the other — and a candidate who fixes each descriptive name to the feature it names is far less likely to attach it to the wrong modern equivalent under time pressure.

Concept: Family names in botany are normally formed from the name of an included genus, the type genus, with the ending -aceae substituted for the genitive ending — Rosaceae from Rosa, Solanaceae from Solanum, Asteraceae from Aster. Before that convention was settled, several large and familiar families had acquired names describing a conspicuous character of the group instead, and because those names were entrenched in the literature the International Code of Nomenclature for algae, fungi and plants allows eight of them to remain in use as alternatives to the standardised forms. The eight are Palmae for Arecaceae, Gramineae for Poaceae, Cruciferae for Brassicaceae, Leguminosae for Fabaceae, Guttiferae for Clusiaceae, Umbelliferae for Apiaceae, Compositae for Asteraceae and Labiatae for Lamiaceae; Papilionaceae is permitted in a related way for the subfamily of Fabaceae. Each old name records the character it was coined for: Gramineae the grasses, Cruciferae the four petals set in a cross, Leguminosae the legume pod, Umbelliferae the umbel, Compositae the composite head of florets, Labiatae the lipped corolla, Guttiferae the drops of resin the plants exude. Each modern name records instead a genus: Poa, Brassica, Faba, Apium, Aster, Lamium, Clusia, Areca. The families themselves are among the most important in the flora and in agriculture — Poaceae supplies the cereals, Fabaceae the pulses and the nitrogen-fixing legumes, Brassicaceae the mustards and crucifer vegetables, Asteraceae is one of the two largest families of flowering plants alongside Orchidaceae, and Apiaceae supplies a large share of the spice crops.

State PCS 2023 Q67 — Science & Technology PYQ with Answer

State PCS 2023 Q67 — Science & Technology PYQ with Answer