, ▁the ▁Swedish ▁botan ist ▁who ▁first ▁formally ▁described ▁the ▁species , ▁named ▁it ▁after ▁its ▁rec ur ved ▁ped un cles ▁which ▁give ▁the ▁flowers ▁a ▁nod ding ▁( nut ans ▁in ▁Latin ) ▁appearance . ▁ ▁Description ▁It ▁is ▁a ▁bush ▁ ▁in ▁height . ▁Its ▁branches ▁have ▁incon sp ic uous , ▁brown ▁l entic els . ▁ ▁Its ▁memb ran ous , ▁o val ▁leaves ▁are ▁ 3 - 5 ▁by ▁ 2 . 5 - 3 . 2 ▁cent im eters ▁with ▁rounded ▁a pe x ▁that ▁ends ▁in ▁an ▁ab rupt ▁small ▁point . ▁ ▁The ▁leaves ▁are ▁hair less ▁on ▁their ▁upper ▁surface ▁and ▁on ▁their ▁lower ▁surface ▁except ▁along ▁the ▁mid rib ▁and ▁ve ins ▁when ▁young . ▁ ▁The ▁leaves ▁have ▁ 1 0 ▁secondary ▁ve ins ▁em an ating ▁from ▁each ▁side ▁of ▁the ▁mid rib . ▁ ▁Its ▁pet i oles ▁ 2 ▁mill im eters ▁long ▁and ▁have ▁a ▁gro ove ▁on ▁their ▁upper ▁side . ▁ ▁Its ▁rec ur ved ▁ped un cles ▁are ▁ 2 . 5 - 4 ▁cent im eters ▁long , ▁extra - ax ill ary ▁and ▁usually ▁emer ge ▁opposite ▁a ▁leaf . ▁ ▁The ▁ped un cles ▁are ▁solit ary ▁or ▁in ▁pairs . ▁ ▁The ▁ped un cles ▁have ▁a ▁b ract , ▁covered ▁in ▁rust ▁colored ▁hair s , ▁at ▁their ▁base ▁and ▁another ▁at ▁their ▁mid point . ▁ ▁Its ▁sep als ▁are ▁un ited ▁to ▁form ▁a ▁cal y x