Which Samas (समास) is present in the compound word 'पर्णकुटी'?

The compound 'पर्णकुटी' can be expanded (समास विग्रह) as:
$$\text{पर्ण से बनी कुटी}\text{ (A hut made of leaves)}$$

Since it uses case/relation postpositions to link the components and emphasizes the second word (उत्तरपद प्रधान), it is categorized under Tatpurush Samas (specifically, Tratiya/Karan Tatpurush or Sambandh-based descriptive sub-types).