▁very ▁w axy ▁on ▁the ▁surface . ▁The ▁flow ering ▁st alk ▁is ▁up ▁to ▁ 4 5   cm ▁tall , ▁bearing ▁an ▁um bel ▁of ▁ 8 - 1 1 ▁flowers . ▁The ▁flowers ▁are ▁white ▁with ▁a ▁white ▁stam inal ▁cup ▁(= ▁memb rane ▁connecting ▁the ▁fil aments ) ▁ 1 8 – 2 1   mm ▁high . ▁ ▁Tax onomy ▁ ▁The ▁species ▁was ▁first ▁described ▁in ▁ 1 9 9 8 ▁by ▁Joseph ▁E . ▁La fer rière . ▁The ▁ep ith et ▁" cl iv orum " ▁means ▁" of ▁the ▁s lop es ." ▁The ▁ep ith et ▁is ▁gram matically ▁a ▁gen itive ▁n oun ▁rather ▁than ▁an ▁ad jective , ▁thus ▁explaining ▁the ▁"- orum " ▁ending ▁despite ▁the ▁femin ine ▁generic ▁name . ▁ ▁Distribution ▁and ▁habitat ▁ ▁Many ▁of ▁the ▁species ▁of ▁the ▁genus ▁grow ▁in ▁sw amps ▁and ▁along ▁stre amb anks ▁in ▁the ▁war mer ▁parts ▁of ▁the ▁Western ▁Hem is phere , ▁especially ▁in ▁Mexico , ▁the ▁Car ib bean ▁and ▁the ▁sout he astern ▁United ▁States . ▁Only ▁two ▁other ▁species ▁are ▁known ▁from ▁Son ora : ▁H . ▁p im ana ▁grows ▁in ▁grass y ▁fields ▁in ▁the ▁Sierra ▁Mad re ▁Occ ident al ▁along ▁the ▁line ▁with ▁Ch ih u ah ua ; ▁H . ▁son or ensis ▁along ▁stream ▁banks ▁in ▁southern ▁Son ora ▁and ▁in ▁S inal oa . ▁H ymen oc all is ▁cl iv orum , ▁however , ▁is ▁found ▁on