How 'bout something to brighten up your shady garden?  Even when it's not showing off it's 1" brilliant yellow blooms,  Viola hastata lights up the darkness with resplendent silvery mottling on its foliage.  Sort of like snowflakes,  each plant is slightly different.

Very east to grow in average soil,  here is a plant that doesn't require much attention. And don't worry about it taking over your garden,  Viola hastata is very well behaved,  unlike some of its brethren.

The specific epithet hastata refers to the sword like shape of the leaves,  which taper to a point and are wider at the bottom. If you've ever wondered about the scientific names used to describe the different shapes of leaves,  you'll just love the chart of leaf shapes at: http://www.m-w.com/mw/art/leaf.htm

The common name,  "Halberd Leaved Violet",  comes from the resemblance to a "Halberd",  which was a sword like weapon used ceremonially in ancient times.  You can learn more at http://www.apva.org/ngex/c9halb.html

Although I couldn't find any specific medicinal uses of Viola hastata,  my friend Scott Appell has written an article that you'll find very interesting about the ethnobotanical uses of Viola by Native Americans. You can find this informative, illustrated piece at :
http://www.americanvioletsociety.org/Violets_In_America/Ethnobotanical.htm

Propagation of Viola hastata is easiest by division of the small,  brittle, creeping rhizome that kind of looks like bright white grub worms.

Taxonomic Hierarchy
Kingdom - Plantae - Plants
Subkingdom - Tracheobionta - Vascular plants
Superdivision - Spermatophyta - Seed plants
Division - Magnoliophyta - Flowering plants
Class - Magnoliopsida - diocotyledons
Subclass - Dilleniidae
Order - Violales
Family - Violaceae - Violets
Genus - Viola
Species - hastata
Common name - genus - "Violets"
Common name - species - "Halberdleaf Yellow Violet"
Synonyms - none that I have found
Native range - see - http://plants.usda.gov/cgi_bin/plant_profile.cgi?symbol=VIHA2
USDA Hardiness Zone - zone 5, most likely 4, maybe 3
Light preference - Full shade to dappled sunlight
Soil fertility preference - Average
Soil moisture preference - Average to well drained
Bloom time - Mid to late spring
Bloom color - Bright Yellow
Foliage - Medium green, silvery mottling patterns
Spread - 4"-8" clump
Height - 4" - 8"
Landscape uses - Naturalizing in a shade or woodland garden
Medicinal uses - none that I have found