Ask Mr. Smarty Plants

Here is some information from the answer to a previous question about chlorine/chloride-tolerant plants:

"In Symptoms of Deficiency in Essential Minerals in A Companion to Plant Physiology (OnLine), 4th Edition by Lincoln Taiz and Eduardo Zeiger, Wade Berry says that "Plants are generally tolerant of chloride..." and listed some plants that are sensitive to chloride (avocados, stone fruits and and grapevines). He also wrote that "Chloride is very abundant in soils, and reaches high concentrations in saline areas...".  By the way, chlorine and chloride are often used interchangeably, but chlorine is the element and not really found free in nature.  It is found as chloride  in the form of its salts (e.g., NaCl—sodium chloride or table salt is the commonest form)."

This would be a good indication that you could use salt-tolerant plants with good effect in areas where chlorinated water is a problem.   Now all we have to do is find plants that do well in shade, high summer temperatures with humidity and cold, dry winters with possible abuse from visitors and are not poisonous!!

We'll start by looking at the Missouri Recommended list of native plants suitable for landscaping in Missouri.  We can use the NARROW YOUR SEARCH option to find plants that do well in shade and part shade.  You may also want to divide it up to look for plants that prefer moist soil (nearer the standing or running water) and drier soils away from the water.  For instance, choosing "Moist" will narrow down the list by about 1/3 and you can narrow even more by choosing the type of plants under GENERAL APPEARANCE (e.g., Tree, Herb, Fern, etc.). 

By cross-referencing between other databases we can find some plants that will meet all, or most, of your criteria.  For salt tolerance:

• The Morton Arboretum in Illinois has a list of trees and shrubs that are salt-tolerant.  You can compare the trees on the Missouri Recommended list to those on the Morton Arboretum list.  Note that some of the trees listed by Morton Arboretum are NOT native.
• North Carolina State University Cooperative Extension also has a list of Salt Tolerant Plants that includes trees, shrubs, vines, ornamental grasses and perennials.  You can use this list to check against the Missouri Recommended list. Plants that are further from the water source will require less tolerance for salt/chloride.   Again, this list contains some plants that are NOT native.
• Jost Greenhouses in Des Peres, MO has a list of salt-tolerant plants.  Again, some on the list are not native.

There are several poisonous plants databases that you can use to check the toxicity of any plant:

• Poisonous Plants of North Carolina

• Canadian Poisonous Plants Information System

• University of Pennsylvania's Poisonous Plants

• Illinois Toxic Plants

Using this approach, here are some plants that do meet some of your criteria: 

TREES

Acer saccharinum (Silver maple) is moderately tolerant of aerial salt; will grow in shade, part shade or sun and is not on any of the toxic plant databases listed above.

Catalpa speciosa (Northern catalpa) is tolerant of soil salt and aerial salt; grows in part shade and isn't on any of the toxic plant databases.

SHRUBS

Amorpha fruticosa (Indigo bush) grows in sun or part shade; is salt-tolerant and does not appear on the toxic plant databases.

Rhus aromatica (Fragrant sumac) grows in sun, part shade or shade; tolerates both soil and aerial salt; and is not on a toxic plant database.

Viburnum prunifolium (Blackhaw) grows in part shade; is soil salt tolerant and moderately aerial salt-tolerant; and doesn't appear on any toxic plant list.

PERENNIAL HERBS

Echinacea purpurea (Eastern purple coneflower) is slightly salt-tolerant, grows in part shade and is not on a toxic plant list. 

Aquilegia canadensis (Eastern red columbine) is salt-tolerant; grows in shade and part shade and doesn't appear on the toxic plant databases. 

Finally, if there is a particular plant that you like on the Missouri Recommended list and you haven't found it on any of the salt tolerant lists, you can search for the plant online by its scientific name combined with "salt tolerant".  If a plant doesn't appear on one of the toxic plant databases above, it is likely that it isn't dangerously poisonous.