Must you have the 'Mendenhall' cultivar? If so, lotsa luck.

However, Bergstrom Orchids has the species for $25.

www.bergstromorchids.com/Catalog.htm

A trick for searching for plants you want to buy: go to
www.google.com, and enter a search string like this:

"Phalaenopsis lindenii" price

Use the quotes to get the species you want, and the word "price"
gets you where you're going. Ah, capitalism.

-AJHicks
Chandler, AZ