Page 27. " the region "

US Cold War Propaganda
Public DomainUS Cold War Propaganda - Credit: US Government
The U.S.S.R. (Union of Soviet Socialist Republics), or Soviet Union, was the primary enemy of Western states, including Britain and the USA, during the Cold War.

The Cold War was characterised by significant distrust, suspicion and ignorance (promulgated in propaganda such as the triffid-like poster pictured). It was designated a cold war because the primary enemies never fought each other directly, although proxy conflicts arose in satellite states such as Korea and Vietnam.

Page 28. " with something like twenty-five million new mouths bawling for food every year "
Population Explosion
Creative Commons Attribution Share AlikePopulation Explosion - Credit: K.boroshko

Though the concept of 'the population explosion' was not in vogue when this novel was written (Paul Ehrlich's The Population Bomb was not published until 1968), Wyndham makes it clear that the consequences of rapidly increasing human numbers were starting to worry people.

The 1950s was the decade in which the human population began rapidly to escalate: at the beginning of the decade the world's population was about 2.3 billion; it increased to nearly 3 billion by 1960. Wyndham's 25 million extra mouths per year was correct in 1951, but the rate of increase jumped to nearly 50 million more each year during that decade.

Page 28. " The factor which had caused the militant five percent to relax a while from fomenting discord was the satellites. "

Creative Commons Attribution Share AlikeSatellite - Credit: Poppy
Wyndham shows some prescience here. At the time of publication (1951), no man-made satellite had yet been launched into space. The first satellite to be successfully put into orbit was the Soviet Sputnik 1 in 1957.

Page 32. " under a man called Lysenko "

 Trofim Lysenko was in charge of the Soviet Union's biology program under Stalin.

Lysenko was an agronomist who favoured Mendelian genetic manipulation. Soviet biologists were particularly interested in plant hybridisation.

Page 34. " in the district of Elovsk in Kamchatka "

Creative Commons Attribution Share AlikeKamchatka - Credit: Marmelad
The Kamchatka Peninsula is indeed remote from the main population centres in Russia, being at the most eastern tip of the country.  An area rich with volcanoes, it was declared a closed military zone following WW2.

Because of its abundant wildlife, varied climate and winter activities, it is becoming popular with tourists.

Page 38. " took place in Indo-China "

Indochina referred to the French colonies in what is now Vietnam, Laos and Cambodia.

Page 44. " The largest specimen ever observed in the tropics stood nearly ten feet (a little over 3 metres) high. No European specimen over eight feet (2.4 metres) had been seen. "

This is in opposition to a biological observation known as Bergmann's Rule, which states that within a widely distributed genus, species in colder regions tend to be larger than those in warmer regions. However Bergmann's Rule is mainly applied to birds and mammals (such as humans).