Bulgaria

Sparganium fluctuans (floating bur-reed)
Sparganium hyperboreum (northern bur-reed)
Spartina gracilis (alkali cordgrass)
Spartina maritima (small cordgrass)
Spartina patens (saltmeadow cordgrass)
Spartina pectinata (prairie cordgrass)
Spathiphyllum wallisii
Spergula arvensis
Spergularia canadensis var. canadensis (Canadian sandspurry)
Spergularia salina (salt sandspurry)
Spermacoce glabra (smooth false buttonweed)
Spermolepis divaricata (roughfruit scaleseed)
Spermolepis inermis (Red River scaleseed)
Sphenopholis nitida (shiny wedgescale)
Sphenopholis obtusata (prairie wedgescale)
Sphenopholis pensylvanica (swamp wedgescale)
Sphenopholis x pallens
Spiraea alba (white meadowsweet)
Spiraea japonica (Japanese meadowsweet)
Spiranthes cernua (nodding lady's tresses)
Spiranthes lacera var. gracilis (northern slender lady's tre
Spiranthes ovalis var. ovalis (October lady's tresses)
Spiranthes praecox (greenvein lady's tresses)
Spiranthes romanzoffiana (hooded lady's tresses)
Spiranthes vernalis (spring lady's tresses)
Spirodela polyrhiza
Sporobolus clandestinus (rough dropseed)
Sporobolus compositus var. compositus (composite dropseed)
Sporobolus compositus var. drummondii (Drummond's dropseed)

Image of Bulgaria 1
Flags of the World From the World Factbook 2009 Public Domain Image