There is no diference but yellowish Apple green color in petals the first days, (while it opens) in fma manzurii. After a week open you cannot distinguish both. Some clnes of schlimii fma manzurii show rounder staminode but this is strongly dependent on the temperature you grow them so it cannot be used as a taxonomic character. (cooler temperaturas gives rounder staminode)
Also some populations of true schlimii from the Central Cordillera show rounded staminodes so if someone wants to keep manzurii as a true species should provide more tan a vague descripton without a key.
The key we are using right now is as follows but it is not Stone-written:
1-Spherical pouch + Fenestrations: schlimii (fma manzurii if it show yellowish petals)
2-Spherical Pouch without fenestrations: fischeri (some plants labelled as fischeri, specially the ones coming from Colombia can have a very small fenestration hidden under the synsepal). This populatios are close enough to the anguloi populations so it is posible some degree of hybridation (I am studying this topic right now).
3-Laterally compressed pouch (claceolar) without fenestrations: andreettae
4-Laterally compressed pouch (calceolar) + strong fenestrations: anguloi.
Hope it helps!