Both Flora of Taiwan and Flora of China differentiate the two black fruited species like this:
S. americanum: fruiting calyx strongly reflexed; fruit mostly less than 8 mm across, shiny. S. nigrum: fruiting calyx mostly applied to the berry, berry dull, 8-10 mm across To my knowledge calyx in S. americanum is shorter than S. nigrum These links should help Solanum americanum: http://delta-intkey.com/solanum/images/sol_ame_3850.jpg http://delta-intkey.com/solanum/images/sol_ame_3846.jpg http://www.hear.org/starr/images/image/?q=010520-0074&o=plants Solanum nigrum: http://www.homeopathyandmore.com/forum/viewtopic.php?t=3651 http://www.rbgsyd.nsw.gov.au/science/Evolutionary_Ecology_Research/Ecology_of_Cumberland_Plain_Woodland/woodland_plants/solanum_nigrum http://b-and-t-world-seeds.com/carth.asp?species=Solanum nigrum&sref=5674 -- Dr. Gurcharan Singh Retired Associate Professor SGTB Khalsa College, University of Delhi, Delhi-110007 Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018. Phone: 011-25518297 Mob: 9810359089 http://people.du.ac.in/~singhg45/ On Mon, Nov 15, 2010 at 9:49 PM, Pankaj Kumar <[email protected]>wrote: > SOURCE: wikipedia > > American nightshade can be confused with a variety of other related > nightshades. Here is a quick guide for differentiating between > species. > > American nightshade (Solanum americanum) > The undersides of its hairy leaves are not reddish-purple. The berries > are speckled with white until it is fully ripe and turns black. > > Black nightshade (Solanum nigrum) > Berries are purple or dark green and dull. They are almost completely > exposed (very small calyx). > > Eastern black nightshade (Solanum ptycanthum9 > The undersides of the leaves are reddish purple and the berries are dark. > > Hairy nightshade (Solanum villosum) > Berries are light green or yellow when ripe and the leaves are so > hairy that they may feel sticky. > > With this info on wikipedia I think I would still prefer to go with > Solanum nigrum as I dont find hairs on the lower surface of leaf, > though the picture is not good and secondly I will consider those > bracts as small and fruits completely exposed. > > Regards > Pankaj > > > -- > *********************************************** > "TAXONOMISTS GETTING EXTINCT AND SPECIES DATA DEFICIENT !!" > > > Pankaj Kumar Ph.D. (Orchidaceae) > Research Associate > Greater Kailash Sacred Landscape Project > Department of Habitat Ecology > Wildlife Institute of India > Post Box # 18 > Dehradun - 248001, India >
