Some are seen only after a field fire, some are seen better after one, such as, in South Africa, Disa racemosa, Satyridium rostratum, Evota bicolor, a sp. of Pterostylis, Diuris, Prasophyllum, Lyperanthus, Thelymitra and Caladenia; smoke containing about lOO ppm. of ethylene and 2000ppm. carbon monoxide breaks dormancy in non-orchids such as freesia bulbs. SA86Mar-8