▁W ahoo , ▁Neb r aska , ▁while ▁he ▁studied ▁at ▁the ▁University ▁of ▁Neb r aska . ▁He ▁graduated ▁from ▁the ▁University ▁of ▁Neb r aska ▁( B . S . ▁in ▁ 1 8 9 1 ) ▁and ▁( M . A . ▁in ▁ 1 8 9 5 ). ▁He ▁earned ▁his ▁gradu ate ▁degree ▁from ▁Columbia ▁University ▁( Ph . D . ▁in ▁ 1 8 9 8 ). ▁▁▁ ▁So on ▁after ▁he ▁graduated , ▁R yd berg ▁received ▁a ▁commission ▁from ▁the ▁United ▁States ▁Department ▁of ▁Agricult ure ▁to ▁undert ake ▁a ▁botan ical ▁expl oration ▁of ▁western ▁Neb r aska . ▁He ▁received ▁another ▁one ▁in ▁ 1 8 9 2 ▁to ▁explore ▁the ▁Black ▁Hills ▁of ▁South ▁Dak ota , ▁and ▁in ▁ 1 8 9 3 ▁he ▁was ▁in ▁the ▁Sand ▁Hills , ▁again ▁in ▁western ▁Neb r aska . ▁During ▁this ▁time ▁he ▁continued ▁to ▁teach ▁at ▁the ▁Luther ▁Academy . ▁▁ ▁In ▁ 1 9 0 0 ▁R yd berg ▁conducted ▁field ▁work ▁in ▁sout heast ▁Colorado . ▁In ▁ 1 9 0 1 ▁he ▁visited ▁K ew ▁Gard ens ▁in ▁England ▁and ▁made ▁a ▁return ▁trip ▁to ▁Sweden ▁as ▁well . ▁In ▁ 1 9 0 5 ▁he ▁was ▁collect ing ▁in ▁Ut ah ▁with ▁vis its ▁to ▁the ▁University ▁of ▁Wy oming , ▁Los ▁Angeles , ▁and ▁San ▁Francisco . ▁In ▁ 1 9 1 1 ▁he ▁under to ok ▁an ▁expl oration ▁of ▁sout heast ▁Ut ah ▁and ▁in