The incontestable proof is in the Georgics, where Virgil tells us at what season we must sow the _faselus_.

He says:-- Si vero viciamque seres vilemque faselum ...
Haud obscura cadens mittet tibi signa Bootes; Incipe, et ad medias sementem extende pruinas.
Nothing is clearer than the precept of the poet who was so admirably familiar with all matters agricultural; the sowing of the _faselus_ must be commenced when the constellation of Bootes disappears at the set of sun, that is, in October; and it is to be continued until the middle of the winter.
These conditions put the haricot out of the running: it is a delicate plant, which would never survive the lightest frost.

Winter would be fatal to it, even under Italian skies.

More refractory to cold on account of the country of their origin, peas, broad beans, and vetches, and other leguminous plants have nothing to fear from an autumn sowing, and prosper during the winter provided the climate be fairly mild.
What then is represented by the _faselus_ of the Georgics, that problematical vegetable which has transmitted its name to the haricot in the Latin tongues?
Remembering that the contemptuous epithet _vilis_ is used by the poet in qualification, I am strongly inclined to regard it as the cultivated vetch, the big square pea, the little-valued _jaisso_ of the Provencal peasant.
The problem of the haricot stood thus, almost elucidated by the testimony of the insect world alone, when an unexpected witness gave me the last word of the enigma.

It was once again a poet, and a famous poet, M.Jose-Maria de Heredia, who came to the aid of the naturalist.
Without suspecting the service he was rendering, a friend of mine, the village schoolmaster, lent me a magazine[9] in which I read the following conversation between the master-sonneteer and a lady journalist, who was anxious to know which of his own works he preferred.
"What would you have me say ?" said the poet.
"I do not know what to say, I do not know which sonnet I prefer; I have taken horrible pains with all of them....