Their extreme reduction in form and loss of sexuality may be correlated with the saprophytic habit, the proteids and other organic material required for the growth and reproduction being appropriated ready synthesized, the plant having entirely lost the power of forming them for itself, as evidenced by the absence of chlorophyll.
The Mycetozoa or Myxomycetes are a saprophytic group without chlorophyll, of simple structure and isolated position.
Those Fungi which are saprophytic can only live when supplied with organic compounds of some complexity, which they derive from decomposing animal or vegetable matter.
It is not sufficient to find bacteria in the rotting tissues, however, nor even to be successful in infecting the plant through an artificial wound, unless very special and critical precautions are taken, and in many of the alleged cases of bacteriosis the saprophytic bacteria in the tissues are to be regarded as merely secondary agents.
The order is well represented in Britain by 18 genera, which include several species of Orchis: Gymnadenia (fragrant orchis), Habenaria (butterfly and frog orchis), Aceras (man orchis), Hermin- ium (musk orchis), Ophrys (bee, spider and fly orchis), Epipactis (Helleborine), Cephalanthera, Neottia (bird's-nest orchis), one of the few saprophytic genera, which have no green leaves, but derive their nourishment from decaying organic matter in the soil, Listens (Tway blade), Spiranthes (lady's tresses), Malaxis (bog-orchis), Liparis (fen-orchis), Corallorhiza (coral root), also a saprophyte, and Cypripedium (lady's slipper), represented by a single species now very rare in limestone districts in the north of England.