document and identify them, assigning a number, which is now known as the Cole number still used today all around the world. They studied and revised the genus, in 1988 publishing a definitive book (Lithops: Flowering Stones) describing the species, subspecies, and varieties which have been accepted ever since. Because their camouflage is so effective, new species continue to be discovered, sometimes in remote regions of Namibia and South Africa, and sometimes in well-populated areas where they simply had been overlooked for generations. Recent discoveries include L. coleorum in 1994, L. hermetica in 2000, and L. amicorum in 2006. Taxonomy Many of the species listed have named subspecies or varieties and some have many regional forms identified by old names or habitat locations. Identification of species is primarily by flower colour and leaf patterns. Gallery References Literature External links Lithops info from the BBC (UK) A guide to the cultivation of Lithops Lithops books and links Lithops gallery Lithops photo album (François Hoes, Belgium) plantesdepedra.com (Catalan info + translator) manolithops.es (Spanish info) Scrapbooklithops (General info & habitat photographs) Articles containing video clips Aizoaceae genera Taxa named by N. E. Brown Succulent plants