There were 3 illustrations found for W. Giess
6 612593 Lithops schwantesii DinterG.C. Nel, Lithops: , fig. 72 (1946) [W. Giess]
6 612564 Lithops lesliei (N.E. Br.) N.E. Br. [125 662353 Mesembryanthemum lesliei N.E. Br.]G.C. Nel, Lithops: p. 14, fig. 12 (1946) [W. Giess]
2 612581 Lithops optica N.E. Br.G.C. Nel, Lithops: p. 21, fig. 13 (1946) [W. Giess]