Dear Friends, Mention should be made of the excellent summary of this topic in "The Woody Iridaceae: Nivenia, Klattia & Witsenia: Systematics, Biology & Evolution" by Peter Goldblatt Timber Press. Check it out. Jim W. -- Dr. James W. Waddick 8871 NW Brostrom Rd. Kansas City Missouri 64152-2711 USA Ph. 816-746-1949 Zone 5 Record low -23F Summer 100F +