It will be clear from the above that the only way of reconciling the religious/ethno-linguistic evidence of Siklós with the sound botanical perspectives of Symon and Haegi was the positing of a pre-Columbian introduction of Datura metel to India, satisfying the requirement for both a homeland in the Americas and a cultural presence in India (and probably also Africa) of considerable antiquity.
It is just such a solution that was provided in 2007 by a highly illuminating paper by scholars R. Geeta (Stony Brook University) and Waleed Gharaibeh (Jordan University of Science and Technology), accessing a wealth of evidence not hitherto available to western botanists (a lack freely acknowledged by Symon and Haegi in their paper of 1991 and noted by Siklós in his critique of their work).
Such a solution is not to be proposed lightly in the academic community, as a consultation of the Wikipedia page Pre-Columbian trans-oceanic contact theories will readily reveal: most such theories fail to meet stringent academic criteria and are dismissed out of hand by specialists in the various fields of study necessarily involved; however it will also be seen that, of such theories, those that have won a measure of academic support often relate to ancient introductions of plants - the most notable case being that of the sweet potato Ipomoea batatas,  evidence for trans-Pacific introductions of which (both Polynesia-to-South America and vice-versa) is now widely accepted.

Geeta and Gharaibeh add the following caveat, certain only of the fact of pre-Columbian introduction and maintaining an open mind as to how this introduction occurred.

...it is important to note that, given Datura was in Asia by the 4th century CE, it must have been transported from America at least 600 or so years before the putative trans-Pacific transport of the sweet potato by 1000 CE.
Clearly, these hypotheses regarding the ancient transport of Datura from somewhere in Mesoamerica to somewhere in India, via either Southeast Asia or Africa, need to be tested using a range of methods: botanical, genetic, cultural, and historical.

Of the possible means of transport by wind, water, bird or human agency, the authors dismiss immediately scenarios involving dispersal by wind or via bird droppings as wholly implausible: the seeds of Datura metel are not only heavy but also lack any specialised adaptation to wind dispersal such as a wing or a pappus, and the fruits of Datura are not juicy berries which invite consumption by birds [unlike those of, for example, the bird-disseminated  Atropa].
The authors settle upon transport by water as by far the most likely mode and, of the two scenarios involving water, human-mediated transportation being the more probable, although not ruling out a scenario whereby the buoyant fruits (and seeds possibly remaining viable after prolonged immersion in salt water) of Datura might have been carried to India by ocean currents.
Another possibility is that Datura capsules might have been rafted naturally across the ocean on floating clumps of vegetation dislodged from their original locations, in the manner noted by Renner et al.
to have occurred in the case of certain other plant species.

As to specific ocean currents which could have transported plant material of Datura metel from the New to the Old World, Geeta and Gharaibeh suggest that transport by the Gulf Stream followed by capture by the Canary Current could have brought the plant first across the Atlantic Ocean to Africa.

By contrast, a possible human-mediated route would involve first eminently feasible land transport from Mexico to Ecuador and Peru (borne out by observations of the ritual use of Datura in these South American countries), followed by water transport across the Pacific Ocean from South America to Oceania (as is recognised to have taken place in the case of the sweet potato) and finally from Oceania to Southeast Asia and South Asia.

We need to examine the history of the plant's presence in both cases
(Africa and South East Asia/Polynesia) in order to assess the plausibility
It will be clear from the above that the only way of reconciling the religious/ethno-linguistic evidence of Siklós with the sound botanical perspectives of Symon and Haegi was the positing of a pre-Columbian introduction of Datura metel to India, satisfying the requirement for both a homeland in the Americas and a cultural presence in India (and probably also Africa) of considerable antiquity. It is just such a solution that was provided in 2007 by a highly illuminating paper by scholars R. Geeta (Stony Brook University) and Waleed Gharaibeh (Jordan University of Science and Technology), accessing a wealth of evidence not hitherto available to western botanists (a lack freely acknowledged by Symon and Haegi in their paper of 1991 and noted by Siklós in his critique of their work). Such a solution is not to be proposed lightly in the academic community, as a consultation of the Wikipedia page Pre-Columbian trans-oceanic contact theories will readily reveal: most such theories fail to meet stringent academic criteria and are dismissed out of hand by specialists in the various fields of study necessarily involved; however it will also be seen that, of such theories, those that have won a measure of academic support often relate to ancient introductions of plants - the most notable case being that of the sweet potato Ipomoea batatas,  evidence for trans-Pacific introductions of which (both Polynesia-to-South America and vice-versa) is now widely accepted.
Geeta and Gharaibeh add the following caveat, certain only of the fact of pre-Columbian introduction and maintaining an open mind as to how this introduction occurred.
...it is important to note that, given Datura was in Asia by the 4th century CE, it must have been transported from America at least 600 or so years before the putative trans-Pacific transport of the sweet potato by 1000 CE. Clearly, these hypotheses regarding the ancient transport of Datura from somewhere in Mesoamerica to somewhere in India, via either Southeast Asia or Africa, need to be tested using a range of methods: botanical, genetic, cultural, and historical.
Of the possible means of transport by wind, water, bird or human agency, the authors dismiss immediately scenarios involving dispersal by wind or via bird droppings as wholly implausible: the seeds of Datura metel are not only heavy but also lack any specialised adaptation to wind dispersal such as a wing or a pappus, and the fruits of Datura are not juicy berries which invite consumption by birds [unlike those of, for example, the bird-disseminated  Atropa]. The authors settle upon transport by water as by far the most likely mode and, of the two scenarios involving water, human-mediated transportation being the more probable, although not ruling out a scenario whereby the buoyant fruits (and seeds possibly remaining viable after prolonged immersion in salt water) of Datura might have been carried to India by ocean currents. Another possibility is that Datura capsules might have been rafted naturally across the ocean on floating clumps of vegetation dislodged from their original locations, in the manner noted by Renner et al. to have occurred in the case of certain other plant species.
As to specific ocean currents which could have transported plant material of Datura metel from the New to the Old World, Geeta and Gharaibeh suggest that transport by the Gulf Stream followed by capture by the Canary Current could have brought the plant first across the Atlantic Ocean to Africa.
By contrast, a possible human-mediated route would involve first eminently feasible land transport from Mexico to Ecuador and Peru (borne out by observations of the ritual use of Datura in these South American countries), followed by water transport across the Pacific Ocean from South America to Oceania (as is recognised to have taken place in the case of the sweet potato) and finally from Oceania to Southeast Asia and South Asia.
We need to examine the history of the plant's presence in both cases
(Africa and South East Asia/Polynesia) in order to assess the plausibility
Datura metel