A chance remark on a friend’s blog prompted me to try and pick up a trail that had gone quite cold. Her friend was remarking that “the dates groves that flourish in Mexico’s Baja California oases were first planted by the Jesuit missionaries with seeds from North Africa”. Vavilov’s contact in Algeria, Louis Trabut, is credited with helping to introduce “hundreds of Algerian plants” into the US, among them the dates alluded to by a commenter on Rachel’s blog post. Back in 2009 I tried following this up but didn’t get very far; now I have, thanks to the Biodiversity Heritage Library.
Two early publications deal with the introduction of dates into the US. Walter Swingle’s The date palm and its utilization in the southwestern states (1904) I’m going to leave for now, not least because I want to give Rachel a fair crack at the whip. Date growing in the old world and the new, by Paul B. Popenoe (1913), however, proved irresistible, for one of the appendices: To Grow Bananas from Date Seeds:
“During the dark ages it was a widespread Arab superstition that bananas could, under certain circumstances, be grown from date seeds. The slight similarity in general appearance between the two plants was elevated to a real relationship, particularly by the Baghdád physician ‘Abdu-l Latif (twelfth century), in his Description of Egypt (pub. at Paris by Imperial Press, 1810, with tr. by S. de Sacy). The writer declares that to make the relationship evident all you need to do is to place a date seed in a fruit of the colocasia and bury it; the result will be a banana plant.
“The plant which the Arabs designate as colocasia (Arab., from Pers., qulqás) is doubtless not Colocasia antiquorum,  but the sacred water lily of the Egyptians, Nymphea lotus (Castalia mystica). The way in which the writers speak of it shows, however, that they had only a hazy idea in mind, and probably did not really know what plant they were referring to.
“Ibn Awám, the Spanish Moor who wrote his treatise on agriculture in the twelfth century, gives more detailed directions for performing the operation, in his chapter entitled “To Make a Date Seed Grow in a Colocasia Root, to Obtain a Banana by the Permission of God.”  He says:
“The manner of operating is to plant a colocasia root in a place constantly exposed to the sun, where one can water it abundantly and continuously and protect it from wind. Water it carefully until the root sprouts; then dig away the earth, split the root with a gold-bladed knife, and in that cleft introduce the date seed. The operation must be concealed in such a manner that the colocasia root can not see what is being done, otherwise the operation will not succeed. The seed used should be from a date of the variety Kasbeh  or any other delicate variety. Bind up the cut with reed leaves or woolen thread and plaster the whole thing over with mud mixed with fine hairs, then cover it four fingers deep with humus. Water it with sweet water daily or every other day until the germination is apparent, then you will see the banana appear. If planted in January or February you will get fruit at the end of summer; this fact is very extraordinary. Some think the seed should be broken before it is put in the cleft; I have tried it without success.
“A witness worthy of faith tells me he has seen the operation performed in the orient in this manner: Take a seed in its fruit, using pains to get a female seed–it is that which is short and not pointed at the end. Introduce the seed in a colocasia root, which resembles a turnip or artichoke root; cover it with a little humus, water it continuously, and abundantly, and there will appear a banana, which is a kind of colocasia, but rare in Spain, if indeed it is known at all.”
Another MS. version, more probably correct, makes Ibn Awán say that he has never been able to try the operation, because he could not secure any colocasias.”
Why mention this? Certainly not to poke fun at mistaken beliefs. Partly because it’s just fascinating, and I wanted to share. Partly, too, because having learned recently of The Filāḥa Texts Project, and being utterly ignorant of Arabic, I wanted a reason to poke around there. Having done so, I was a bit surprised to see this comment:
“As for my own contribution, I put forward nothing that I have not first proved by experiment on repeated occasions” (Ibn al-‘Awwām, Clément-Mullet 1866, I, p. 9). He records, for example, his experiments in grafting the wild olive of the mountains with the domesticated olive of the plain, and his successful cultivation of saffron, under irrigation, in the mountains (Bolens 1981, p. 30).
Popenoe’s doubts then make sense, but I’m singularly ill-equipped to know; maybe an authentic Arab scholar can help.