, ▁with ▁two ▁large ▁pet al - like ▁sep als ▁on ▁the ▁sides , ▁often ▁called ▁the ▁" w ings ", ▁and ▁three ▁smaller ▁sep als ▁behind . ▁There ▁are ▁three ▁pet als ▁in ▁sh ades ▁of ▁re dd ish ▁pur ple , ▁yellow ▁or ▁white , ▁which ▁are ▁joined ▁at ▁the ▁bases . ▁The ▁lower ▁of ▁the ▁three ▁is ▁the ▁ke el ▁pet al , ▁which ▁is ▁" bo at - sh aped , ▁c uc ull ate ▁[ hood - like ], ▁or ▁hel met - sh aped ". ▁The ▁ke el ▁pet al ▁may ▁have ▁a ▁be ak ▁or ▁a ▁fr inge ▁on ▁the ▁tip . ▁St am ens ▁and ▁style ▁are ▁within ▁the ▁curve ▁of ▁the ▁ke el ▁pet al . ▁The ▁fruit ▁is ▁a ▁caps ule , ▁sometimes ▁wing ed . ▁It ▁contains ▁two ▁se eds , ▁which ▁are ▁usually ▁black , ▁hair y ▁and ▁t ipped ▁with ▁a ▁large ▁white ▁ar il . ▁No ▁members ▁of ▁this ▁genus ▁are ▁known ▁to ▁form ▁nit ro gen - fix ing ▁nod ules . ▁ ▁Tax onomy ▁The ▁genus ▁Pol yg ala ▁was ▁first ▁described ▁by ▁Carl ▁Lin na eus ▁in ▁ 1 7 5 4 . ▁Ph y log en etic ▁studies ▁showed ▁that , ▁as ▁tradition ally ▁circ ums cribed , ▁the ▁genus ▁was ▁not ▁mon oph y let ic . ▁It ▁had ▁become ▁a ▁" w aste b asket ▁tax on "; ▁almost ▁all ▁species ▁with ▁a ▁flower ▁apparently ▁similar ▁to ▁those ▁of ▁the ▁Pap il iono