J. J.  Spies and H. Plessis, D., ?Chromosome studies on African plants. 3?, Bothalia, vol. 17, pp. 131-135, 1987.

J. J.  Spies, H. Plessis, D., and Barker, N. P., ?Spies (1990)?, Genome, vol. 33, pp. 646-658, 1990.

J. J.  Spies and Jonker, A., ?Chromosome studies on African plants. 4?, Bothalia, vol. 17, pp. 135-136, 1987.

J. J.  Spies, Klopper, K. C., and Visser, B., ?Apomixis in the genus Pentaschistis (Arundinoideae)?, Bothalia, vol. 29, pp. 203-209, 1999.

J. J.  Spies, Saayman, E. J. L., Voges, S. P., and Davidse, G., ?Chromosome studies on African plants. 9. Chromosome numbers in Ehrharta (Poaceae:Ehrharta)?, Bothalia, vol. 19, pp. 125-132, 1989.

J. J.  Spies, Troskie, T. H., van der Vyver, E., and van Wyk, S. M. C., ?Chromosome studies on African plants.  11. The tribe Andropogoneae (Poaceae:Panicoideae)?, Bothalia, vol. 24, pp. 241-246, 1994.

J. J.  Spies, E. Merwe, vandee, H. Plessis, D., and Saayman, E. J. L., ?Basic chromosome numbers and polyploid levels in some South African and Australian grasses (Poaceae)?, Bothalia, vol. 21, pp. 163-170, 1991.

J. J.  Spies, E. Merwe, vandee, H. Plessis, D., and Saayman, E. J. L., ?Basic chromosome numbers and polyploid levels in some South African and Australian grasses (Poaceae)?, Bothalia, vol. 21, pp. 163-170, 1991.