'Vegetation is the true index of climate'. This statement is associated with

1. A

   Thornthwaite

   (a) Thornthwaite. C. W. Thornthwaite classified climates by precipitation effectiveness and thermal efficiency, not by the slogan that vegetation is the true index.

2. B

   Koppen

   (b) Koppen. Wladimir Köppen built his climate types from plant-cover boundaries, stating that vegetation is the true index of climate. That stored name is the official key. Letters A–E follow tropical to polar plant realms.

3. C

   Trewartha

   (c) Trewartha. G. T. Trewartha modified Köppen to reduce the mid-latitude sprawl; he did not coin this index slogan as the source.

4. D

   Stamp

   (d) Stamp. L. Dudley Stamp is remembered for land-use survey in Britain and Indian regional geography, not this vegetation-index dictum.

Summary. Official key is (b) Koppen. The line ‘vegetation is the true index of climate’ is tied to Köppen’s scheme. Thornthwaite, Trewartha and Stamp are other climate or land-use names. Neighbouring codes are Af rainforest and BWh hot desert. Honour Köppen for this paper.