I just received a query about the native range of the Indian Sacred Lotus (Nelumbo nucifera), and whether it might have been introduced to India (e.g. by Indo-Europeans). Here are my thoughts
An introduction to India is not out of the question, but seems fairly unlikely. True there are no hard archaeobotanical finds of Nelumbo [formerly often Nelumbium] but this species is surprisingly rare archaeologically in any case. In favour of an ancient presence in South Asia is the linguistic evidence in Dravidian in which there are cognates in the South, South-Central and Central Dravidian subfamilies (see Dravidian Etymological Dictionary Revised entry 3163), which suggests an original term at a level as early as indigenous South Indian domesticates (Mungbean, horsegram) and many indigenous trees (teak, neem, etc.) [see Fuller 2007 pdf]. The absence of North Dravidian cognates is likely to be poor linguistics recording. These Dravidian, all something like #tamar, are presumably the source of Sanskrit tamarasa (unless one were to posit a shared, older substrate source for both). The true wild distribution is somewhat problematic because today this species is found largely in human-made or modified pools (tanks, etc), but this is to be expected as there are few natural ponds in much of India, where there have been quite dense agricultural populations for a few thousand years. Nelumbo is native in Iran and Southwest Russia, but also extends to East and Southeast Asia, New Guinea and bits of Australia, so a natural presence in India, at least through the Indo-Gangetic river systems seems likely. Archaeobotanically the only really early evidence for lotus that springs to mind is from China, where charred tuber fragments are found at the Neolithic site of Jiahu (7000-6000 BC), where is constitutes part of a aquatic resource package along side Trapa water chestnuts, rice (probably morphologically wild) (as well as wild resources like acorns). There is a brief summary and graph of the Jiahu data published recent in English by 'Jimmy' Zhao in Archaeological & Anthropological Sciences 2.
I would also note that the fossil record is not very informative about where something is native (in the sense of wild prior to human involvement). Of course Nelumbo is present in Tertiary and late Cretaceous India, as it is a very early ('primitive') dictotyledon group, near the base of the lineages that are nowadays called the Eudicots (characterized by tricolpate pollen, as well as genetic monophyly). Nelumbo is in its own family and places in the Proteales (see Angiosperm Phylogeny website). Nelumbanaceae type fossils go back to the Albian, ca. 110 million years, and their presence in Tertiary India is not surprising, as at that time the India subcontinent was an island (formerly of Godwanaland) that was rafting north and had not yet crashed into Asia. Tertiary India included lost of flora which did no persist into the Quaternary: Gunnera is one example that springs immediately to my mind! [see Fuller & Hickey Gunnera paper] Instead, a later Pleistocene and early Holocene fossil record is what is needed to determine where something in 'native'.