</s> ▁Pet rom ar ula ▁is ▁a ▁genus ▁ ▁of ▁plants ▁in ▁the ▁family ▁Camp an ul aceae . ▁There ▁is ▁only ▁one ▁known ▁species , ▁Pet rom ar ula ▁p inn ata , ▁en demic ▁to ▁the ▁island ▁of ▁Cre te ▁in ▁the ▁Mediter rane an . ▁The ▁name ▁" P et rom ar ula " ▁means ▁" rock ▁lett uce " ▁in ▁Greek , ▁a ▁reference ▁to ▁the ▁plant ' s ▁traditional ▁use ▁in ▁sal ads . ▁ ▁Description ▁Pet rom ar ula ▁p inn ata ▁is ▁a ▁robust , ▁medium ▁to ▁tall ▁per enn ial , ▁min utely ▁hair y ▁above . ▁Le aves ▁mostly ▁in ▁a ▁large ▁bas al ▁ro set te , ▁p inn ate ▁to ▁p inn ately - lob ed , ▁the ▁lower ▁long - st alk ed ; ▁leaf lets ▁o val ▁to ▁ob long , ▁co ars ely ▁to oth ed . ▁Flow ers ▁pale ▁blue , ▁ 9 – 1 0   mm , ▁bor ne ▁in ▁large ▁rather ▁narrow ▁pan icles ; ▁cor ol la ▁with ▁ 5 ▁spread ing ▁to ▁rec ur ved ▁linear ▁lo bes . ▁C aps ule ▁opening ▁by ▁ 3 ▁por es ▁in ▁the ▁middle . ▁Flow ers ▁April – May . ▁ ▁Hab itat ▁Rock ▁cre v ices , ▁cl iffs ▁and ▁old ▁walls . ▁ ▁Gallery ▁ ▁References ▁ ▁External ▁links ▁ ▁C ret an ▁Flora , ▁Pet rom ar ula ▁p inn ata ▁Flow ers ▁of ▁Ch ania , ▁Pet rom ar ula ▁p