For those interested, you can search through the collections of herbariums all over north America through portals such as the Consortium of Midwest Herbaria[0], in Europe through digHerb [1], and throughout the rest of the world through many other symbiota portals [2].
You can find your nearest brick and mortar herbarium globally through Index Herbariorum[3]. Though these resources are incomplete, they are pretty extensive regardless.
Also for those in the States, contact your local state University extension office. They know of local resources like this that aren't widely advertised/don't have an online presence.