Nice shot Steve, viewing the flower from behind is unusual but certainly works well.
I've got two very different Industar 50mm/3.5 lens, and there are quite a few more (8 all together according to
http://allphotolenses.com/lenses/brands/c_45.html). Both mine can produce nice photos. Mine are a Industar 50-2 which is in M42 mount (came free with a camera I was after), and a collapsible model in LTM mount (when collapsed it works on Zenit M39, but it's designed to be used extended on rangefinders). The second one cost me nearly £20 with postage, and has proved to be one of my most used lenses.
Which model did you get?