Norma I would not contemplate keeping Sansevieria's at less than 50F
but would prefer 55F at 32F do not water them or they are likely to
rot and when Sansevieria's rot they go at the roots first and by the
time you find out it is usually too late. Those that can take the
cold best are the cylindrical leaved ones.
If I were you and you have the space take your plants indoors leave
them for a week to warm up then water them sparingly about once a
fortnight or three weeks. My plants are kept at 60F min in winter and
I water all year round though not as much as in the summer.
George I have found a picture of the flower on nelsonii (the
species). Took some photo's of nelsonii PF115 and another nelsonii
so I will develop them tonight you should see something tomorrow.
John G