In 1826, in the Memoirs of the Wernerian Natural History Society, Scottish physician and talented natural historian Francis Buchanan-Hamilton scoffed at the descriptions of what we now call Moringa oleifera by Linneaus and others. In the late 1700s and early 1800s, there were so many new plants being discovered and described, often from such fragmentary material, that it was often hard to know to what plant a given name applied. Buchanan-Hamilton got so exasperated with the errors of previous authors -- like Linneaus's mistaking Moringa for a legume, and misinterpretations of the staminodes of Moringa as damaged anthers -- that he regarded all previous moringa names, including M. oleifera, as so ambiguous as to be useless. To provide what he saw as order to the situation, he described two taxa, M. domestica and M. sylvestris. Neither names are used today, and both are regarded as M. oleifera.
But he did succeed in highlighting an intriguing situation. First, his "Moringa sylvestris" is morphologically distinctive- with its uniformly pale seeds with spongy seed coats, it's unlike the usual domestic M. oleifera, which has dark seed bodies and thin seed coats. It is more like the putatively wild M. oleiferas from Punjab, and from what we heard people in Punjab and Uttarakhand refer to as "inedible" moringa. You can see the pale seeds on the specimen below.
It is for these reasons that, after Punjab, Bihar has had the reputation of being special as far as moringa is concerned. From the Buchanan-Hamilton specimens, it does seem that there is an interesting morphological variant in the area (his "M. sylvestris") that seems not unlike the putatively wild plants from Punjab, and from his report as well as that of Haines, it seems that there might even be wild plants in Bihar. The Sameshwar Hills, moreover, are part of the great Shivalik range, on whose low slopes is where the wild moringas of Punjab are found, making it seem possible that wild M. oleifera might reach this far east. The rainfall -- 1500 to 2000 mm -- seemed awfully high for any moringa species, but in botanical exploration there is no alternative- you need to go and have a look.
So, with this in mind, we hopped on a plane from Delhi to Patna, and we weren't disappointed.
So, to summarize, moringas were everywhere in the villages of the Samewshar Hills, but definitely not in the wild habitats. Our conclusion: Haines's riverside plants were associated with humans. Given that they were often on the edges of fields, often fallow ones or ones invaded with weedy trees, it would be easy for someone not paying all his attention to moringa (Haines was, after all, assembling the flora of two whole vast states) to take away the impression of their being wild. But even the riverside habitat would be fishy; no moringas are dependably riparian or even prefer to grow on floodplains (M. arborea does grow in a dry, rocky gully but probably doesn't see water very often). So, we were convinced that there are no wild moringas in the area. Where Buchanan-Hamilton's "Moringa sylvestris" comes from is anyone's guess- perhaps imported long ago from Punjab? Garima's data should shed light on the issue.