The pollination syndrome

Recently I came across a paper on the pollination of the terrestrial orchid Listera ovata and I have observed with pleasure that the author also checked on the ’reverse’ side of pollination, viz. the question whether cross-pollination by insects is compulsory. This reminded me of the large list of Malesian orchids which Dr. J.J. Smith (1928) listed in which he had observed self-fertilization. Flower biologists will probably explain this as exceptions to the rule. So it may be, but how many experimental data are there to support this opinion? They largely base their opinion on observations of flower visits and visitors, how insects and other animals manage to utilize structural plant devices in order to attain their goal, nectar, pollen, scent-substances, etc. They have successfully correlated a number of structures of inflorescences or flowers with flower visitors and they have called these structure ’pollination syndromes’. These occur in taxonomically unrelated families.