i ▁is ▁a ▁slow ▁growing ▁per enn ial ▁that ▁inhab its ▁a ▁wide ▁range ▁of ▁soil ▁substr ates ▁and ▁habitat ▁types . ▁ ▁It ▁can ▁be ▁found ▁below ▁the ▁elev ation ▁of ▁ 5 0 0 0   ft ▁in ▁areas ▁of ▁sand y ▁desert ▁fl ats , ▁rock y ▁hills , ▁or ▁valley ▁grass lands . ▁ ▁Description ▁Op unt ia ▁macro cent ra ▁is ▁an ▁u pr ight ▁spread ing ▁shr ub , ▁usually ▁growing ▁from ▁ ▁tall . ▁ ▁Ind ividual s ▁occasionally ▁reach ▁ ▁in ▁height . ▁ ▁The ▁stem ▁is ▁blue - gray , ▁blue - green , ▁or ▁pur pl ish ▁in ▁color . ▁ ▁The ▁pur ple ▁pad ▁color ▁is ▁the ▁most ▁inten se ▁at ▁the ▁edges ▁of ▁the ▁pad ▁or ▁around ▁the ▁are oles . ▁ ▁The ▁pur ple ▁color ▁comes ▁from ▁the ▁production ▁of ▁a ▁bet al ain ▁( bet acy an in ) ▁p ig ment ▁that ▁becomes ▁more ▁evident ▁as ▁the ▁plant ▁is ▁str essed ▁by ▁dr ought ▁or ▁cold . ▁ ▁P ads ▁The ▁c act us ▁consists ▁of ▁smooth ▁ob ov ate ▁to ▁orb icular ▁sh aped ▁p ads ▁that ▁are ▁connected ▁to ▁each ▁other ▁by ▁the ▁bottom ▁edge ▁or ▁pad ▁margin . ▁ ▁Each ▁pad ▁is ▁from ▁ 1 0 - 2 0 ▁cent im eters ▁in ▁width ▁and ▁ 1 0 - 2 0 ▁cent im eters ▁in ▁length , ▁but ▁is ▁usually ▁wider ▁than ▁it ▁is ▁long . ▁ ▁The ▁are oles , ▁highly ▁reduced ▁branch ▁structures