Thistles in NM

I've compiled a list of common Cirsium species in the lowlands (not mountains) of Southern New Mexico, and mapped their collectioned vouchers from across NM.

Map created using swbiodiversity.org 

Cirsium ochrocentrum – common.  Flower heads are bigger, and petals are longer than C. neomexicanum, often more brilliantly-colored, but plant is smaller.  Flowers usually taller than wide. 

Cirsium neomexicanum  -- Flower head looks more “bushy” because spines are more strongly spreading than on C. ochrocentrum, allowing flower to open more (wider than tall)

Cirsium texanum  - like C. ochrocentrum, but flower heads less than 25mm long, smaller overall.

-Based on Allred's Flora Neomexicana