The head of the Thimble Morel is attached only at the top, so is free from the stem.  The head is wrinkled but is not usually convoluted or pitted, and is a reddish-brown to olive-brown in colour.  The stem is not hollow except at the tip where the head is joined to it.   

The Semifree Morel Morchella semilibera has a hollow stem and the upper part of the head is joined to the stem. 

Photograph in habitat; note substrate and associated tree species.  Ensure your photo show the entirely free head; cutting a vertical section through head and stem is helpful. 

Scrub and woodland, often with Hawthorn

Late spring.