I cannot find a Gladiolus primulinus mentioned in Bryam's book on Bulbs, but there are hybrid ones sold under a similar name.

http://www.backyardgardener.com/plantname/pda_f720.html

Ob may have already said it, but according to the Pacific Bulb Society, G. primulinus is the old name for the yellow form of G. dalenii dalenii:

http://www.pacificbulbsociety.org/pbswiki/index.php/SouthernAfricanGladiolusThree#dalenii