I believe there may be some photos of Dietes grandiflora (??) in the D. iridioides entry. Dietes grandiflora was sold as D. iridioides for many years but it has brown markings on the inner tepals (D. iridioides does not). Ref:
http://www.smgrowers.com/produ...
This shows the flower of iridioides clearly:
http://keyserver.lucidcentral....