cm ▁wide . ▁The ▁leaf ▁she ath ▁is ▁smooth ▁( gl ab r ous ), ▁tap ering ▁to ▁a ▁point . ▁ ▁In ▁its ▁native ▁habit ats , ▁R . ▁h ume ana ▁flowers ▁between ▁April ▁and ▁July . ▁The ▁stem ▁( ped un cle ) ▁of ▁the ▁flower ▁sp ike ▁is ▁hidden ▁by ▁the ▁leaf ▁she ath s . ▁One ▁to ▁many ▁flowers ▁open ▁together ▁and ▁may ▁be ▁of ▁various ▁colours : ▁pur ple , ▁vio let , ▁yellow , ▁p ink ▁or ▁white . ▁The ▁b ract s ▁which ▁subt end ▁the ▁flowers ▁are ▁shorter ▁than ▁the ▁cal y x . ▁ ▁Each ▁flower ▁has ▁the ▁typical ▁structure ▁for ▁Ros co ea ▁( see ▁the ▁diag rams ▁in ▁that ▁article ). ▁There ▁is ▁a ▁long ▁t ube - sh aped ▁outer ▁cal y x , ▁ 1 0 – 1 4   cm ▁long ▁with ▁a ▁two - lob ed ▁a pe x . ▁Next ▁the ▁three ▁pet als ▁( the ▁cor ol la ) ▁form ▁a ▁t ube ▁slightly ▁longer ▁than ▁the ▁cal y x , ▁termin ating ▁in ▁three ▁lo bes , ▁an ▁u pr ight ▁h ood ed ▁central ▁lo be , ▁ 3 – 4   cm ▁long ▁by ▁ 2 . 5 – 3   cm ▁wide , ▁and ▁two ▁slightly ▁smaller ▁side ▁lo bes , ▁ 3 – 3 . 5   cm ▁long ▁by ▁about ▁ 1 . 5   cm ▁wide . ▁Inside ▁the ▁pet als ▁are ▁structures ▁formed ▁from ▁four ▁ster ile