Passion flowers (like Orchids) are a world unto themselves with approximately 500 different species and about as many hybrids. Characterized by a ring of coronal filaments (straight, curvy, spiky, or anything in-between), they appear, to me at least, like flowers from another planet.
When encountering my first Passion flower at a local nursery about 10 years ago, I was impressed enough to return home, get my camera, tripod, etc., go back, and attempt to do it justice. Subsequently I joined the Passiflora Society International, attended one of their annual meetings in Florida, photographed a bunch of different species, and managed to alienate the society president who “never in (his) wildest imagination did (he) guess (I) photographed dead flowers” upon discovering I was working with cut blooms (after he had earlier given me permission).
Whether indoors or out-in-the-field, what is involved here is basically Table-Top Photography. So if you have an actual table top, great; otherwise, the name of the game is Improvise. Any solid surface will do — boxes, stools, apple crates, etc. Believe it or not, at home I often use a garbage can (see “Rings & Things”) that is easy to position with regards to the light.
While my subjects here are Passiflora, I suspect the above can be applied to many other types of flowers.