What Dr. Santhan says is based on the older literature, such as by Beddome etc., where coarse 19th Century species concepts were employed and the two Indian species of Osmunda of the regalis group were both called "O. regalis" - rather like many Indian Dryopteris being called D.filix-mas, or Polystichum being called P. aculeatum - perhaps by homesick British foreigners!
However neither of these two species are actually O. regalis itself and they have been recognised as distinct from O. regalis for a number of decades from 20th Century studies in the 1950s onwards.
The common Himalayan plant is O. japonica and is genetically distinct as well as morphologically so. The veinlets in sterile segments are further apart and the commonest state of O. japonica is to have fully fertile or fully sterile fronds, unlike in O. regalis, and the fertile fronds are considerably shorter and smaller than the sterile ones. They also have a quite different ecology from the bog- and marsh-dwelling O. regalis of Europe, W. Asia and N.W. Africa.
But because, as documented long ago by Japanese botanists, O japonica fairly frequently throws up teratological semi-fertile fronds of various degrees of fertility, it has been confused with O. regalis, including by me earlier on. But the semi-fertile fronds in O. japonica are not like the fronds of O. regalis (which never has fully fertile fronds), as they are shorter with fewer sterile pinnae and usually show abnormalities in having semi-fertile pinnae. I have even seen some where pinnae are sterile at the top and bottom of the frond and fertile in the middle, thus superficially imitating O. cinnamomea subsp. vestita, but not hybrids, simply being abnormalities in the distribution of fertile pinnae in O. japonica.
Some botanists believing that the two species can be "defined" by fully-fertile versus semi-fertile fronds have mistaken these abnormal fronds for O. regalis - and they are the origin of some reports of O. regalis in India, though most such reports are simply based on sterile frond collections of O. japonica. But they are all merely variability in O. japonica, with O. regalis not occurring in the Indian region, but mainly a European species.
However in peninsular and southern India a distinct species occurs, O. hilsenbergii (syn.: O. huegeliana) which consistently has semi fertile sporophylls. This has therefore also been confused, perhaps with more conviction, with O. regalis - not realising that there are other species of the group in the world than just O. regalis and O. japonica. They belong to an Afro-American group including several species in S. and E. Africa (excluding the "European" part in N.W. Africa) and O. spectabilis in N. America. But they differ from O. regalis of Europe by having narrower more lanceolate fronds, smaller, narrower, oblique segments, with the pinnae and pinnules more upwardly sloping and a more delicate frond, with a shorter apical fertile area that is finer and weaker than in O. regalis. As the other writer says, it grows at the edges of lakes, canals and streams unlike O. japonica which likes damp rocks and steep banks at higher altitude. This is the plant that the other writer was thinking of from Karnataka and I have categorised it as a threatened species in India. However it, too, is not at all O. regalis, despite being the origin of many erroneous reports of O. regalis from India.
Chris Fraser-Jenkins.
