the attached picture of plant part found in the trail of wet and shady place. Tried but cant find/locate the plant. Here just upload if some one can identify.
It's difficult to identify without foliage. But the best way is to germinate seeds then send a sample of mature foliage and hopefully flower to a curator of a herbarium :-)
I agree with Dr. Arvind that they could belong to Annonaceae. However, it's more appropriate to include pictures of the leaves as Andrew rightly pointed out.
Images 1 - 3 resemble species of Uvaria etc. while the last image is definitely Annona - very close to Annona senegalensis Pers. and Annona squamosa... Please confirm with your local Flora and/or a herbarium curator in your area.
As leaves are missing, I am not sure, if it is Kadsura at all. However, according to World Checklist of Selected Plant Families (Kew), Kadsura scandens (http://apps.kew.org/wcsp/namedetail.do?name_id=377800 ) does only occur in Malesia (Malaya, Sumatra, Java, Bali). Kadsura heteroclita (http://apps.kew.org/wcsp/namedetail.do?name_id=377783 ) is the only species of this genus known from Bangladesh.
As far as I see, shape of leaves and the branching pattern of the nerves of the leaves of your plant agree quite well with scanned herbarium specimens of Kadsura heteroclita, which were collected in Bangladesh or at least close to it. See http://mediaphoto.mnhn.fr/media/1441302065333d7HQ8ndlg1lJewC8 and http://mediaphoto.mnhn.fr/media/1441302065260PwMgCef6KKmnnmhA