▁from ▁which ▁sp ines ▁and ▁glo ch ids ▁grow , ▁are ▁dark ▁in ▁color ▁can ▁be ▁found ▁arranged ▁in ▁diagonal ▁rows ▁on ▁the ▁midst em ▁segment . ▁ ▁Sp ines ▁are ▁produced ▁on ▁the ▁upper ▁half ▁or ▁the ▁upper ▁edge ▁only ▁of ▁the ▁pad . ▁Each ▁a ero le ▁will ▁have ▁from ▁ 1 - 3 ▁central ▁sp ines ▁coming ▁from ▁it ▁with ▁the ▁longest ▁being ▁ 5 - 1 0 ▁cent im eters ▁in ▁length . ▁ ▁The ▁largest ▁sp ine ▁will ▁be ▁pointed ▁in ▁a ▁marked ly ▁up ward ▁direction . ▁ ▁Sp ines ▁are ▁sometimes ▁seen ▁with ▁a ▁white ▁or ▁yellow ▁tip . ▁ ▁Flow ers ▁are ▁produced ▁on ▁the ▁upper ▁edge ▁of ▁the ▁p ads . ▁ <0x09> ▁ ▁Flow ers ▁Flow ers ▁of ▁Op unt ia ▁macro cent ra , ▁are ▁large ▁st ur dy ▁blo oms ▁of ▁bright ▁colors . ▁ ▁They ▁consist ▁of ▁yellow ▁pet als ▁with ▁red ▁lower ▁port ions ▁forming ▁a ▁bright ▁red ▁center . ▁ ▁The ▁visible ▁internal ▁re product ive ▁structures ▁are ▁pale ▁yellow ▁to ▁cre am ▁in ▁color . ▁ ▁This ▁c act us ▁produces ▁blo oms ▁in ▁late ▁spring , ▁usually ▁April ▁through ▁May . ▁ ▁The ▁blo oms ▁open ▁in ▁the ▁mid mor ning , ▁close ▁at ▁night ▁and ▁do ▁not ▁re open . ▁ ▁F ruit ▁If ▁the ▁flower ▁is ▁pol lin ated , ▁the ▁c act us ▁will ▁produce ▁small ▁o val ▁sh aped ▁f ruits ▁r anging ▁in ▁color ▁from ▁bright ▁red ▁to ▁d ull ▁pur