Learn English – Plant Name Pluralisation

grammatical-numberlatinnounstaxonomy

When one looks at any garden, every plant has an official Latin binomial taxonomical name:

E.g. A favourite of mine, Allium hollandicum – Persian Onion

Now most of those with whom I speak call this particular plant an Allium, this is all well and good until one comes to pluralising the word at which point we divide into those who support traditional Latin pluralisation

Allia (-um endings becoming -a in plurals)

And those who support a modernisation of the terms with the far more common

Alliums (following English's standard pluralisation)

A check of Ngrams shows a once used 'Rhododendra' (The Greek pluralisation would lead you to believe that this is an historically correct plural) while its more standard plural is far more commonly used throughout the last century and a half.
On the other hand, 'Allia' was more frequently used than 'Alliums' until only the 1980s while now-a-days it has fallen at the comparative wayside.
Ngrams analysis

Is there a definitive correct and incorrect pluralisation?

If – as I suspect is the case – it is all rather subjective, are they both acceptable in modern language?

Does this follow through to other species names, e.g. should Homo sapiens be pluralised to Homines sapientes as Latin might suggest?

Best Answer

I think it is safe to concede there is no definitive answer. Per Wikipedia, the trend is toward the informal:

The general trend with loanwords is toward what is called Anglicization or naturalization, that is, the re-formation of the word and its inflections as normal English words. Many nouns (particularly ones from Latin) have retained their original plurals for some time after they are introduced. Other nouns have become Anglicized, taking on the normal "s" ending. In some cases, both forms are still competing.

To make oneself understood, one will adapt to the usage of the community, chatting fondly to neighbours about their alliums and chrysanthemums (while allowing for little jokes in the appropriate strata). There is probably not a uniform answer (i.e., level of anglicization) for all plants and other botanical terms; people still speak and write about arboreta, for example. And, even though mushrooms are not plants, boleti get discussed occasionally (in writing, I presume).

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