Habari nenella ?
I know this is an old thread - I came across it doing a search for African orchids. I grew up in Kenya too and I'm trying to collect orchids from East Africa.
Have you managed to identify your orchid yet? If not there is a lady who may be able to help you. Isobyl la Croix is her name and she spent many years in Eastern Africa researching and studying its orchids. She wrote a book on Kenya's orchids so if anyone will know what it is, she will.
If you do a google search on her name, you should be able to find her email address. (under Uzumara Orchids - its an old out of date list as she doesn,t sell anymore)
She is lovely and terribly helpful!