32GB micro SD not readable WHEN IN adapter

A) 32GB micro SDs (various mfgs) work perfectly in various devices of mine
B) My desktops card reader reads 32GB SDs (NOT microSDs) perfectly
C) Desktop has no slot for micro SDs
D) 1&2GB micro SDs are read perfectly over adapters inserted in my desktop's card reader

HOWEVER, when 32GB micro SDs (see A above) are insert in the adapters I have (see D above), my desktop does not recognize any or them. It does not even issue an error - it's like nothing has been inserted in the card reader.

The adapters (both SanDisk) have the lable:
microSD
microSDHC
microSDXC

I understand 32GB microSDs are microSDHC format, so it would seem that the adapters SHOULD work on them (they work fine on 1&2GB microSDs... AND the card reader itself works fine on 32GB SD's (NOT microSDs)).

I believe I got the 32GB SD's without adapters. Are special adapters needed to accommodate 32GB microSD's?

Advice appreciated, thanks!