Syn.: Brahea minima (Nutt.) H. Wendl., Chamaerops acaulis Michx., Chamaerops arundinacea (Aiton) Sm., Chamaerops glabra Mill., Chamaerops louisiana Darby, Chamaerops sabaloides Baldwin ex Darl., Corypha minor Jacq., Corypha pumila Walter, Rhapis acaulis (Michx.) Walter ex Willd., Rhapis arundinacea Aiton, Sabal adiantina Raf., Sabal deeringiana Small, Sabal floribunda Katzenstein, Sabal glabra (Mill.) Sarg., Sabal louisiana (Darby) Bomhard, Sabal minima Nutt., Sabal pumila (Walter) Elliott
Family: Arecaceae Bercht. et J. Presl

Syn.: Sagittaria esculenta Howell, Sagittaria gracilis Pursh, Sagittaria hastata Pursh, Sagittaria longirostra (Micheli) J. G. Sm., Sagittaria obtusa Muhl. ex Willd., Sagittaria ornithorhyncha Small, Sagittaria planipes Fernald, Sagittaria pubescens Muhl., Sagittaria simplex Pursh, Sagittaria variabilis Engelm., Sagittaria viscosa C. Mohr, Urospatha friedrichsthaliana Schott
Family: Alismataceae Vent.

Syn.: Salix longifolia var. exigua (Nutt.) Bebb, Salix fluviatilis var. exigua (Nutt.) Sarg.
Family: Salicaceae Mirbel

Syn.: Ripselaxis herbacea (L.) Raf.
Family: Salicaceae Mirbel

Syn.: Salix aemulans Seem., Salix reticulata var. nana Andersson, Salix reticulata subsp. nivalis (Hook.) Á. Löve, D. Löve et B. M. Kapoor, Salix reticulata var. nivalis (Hook.) Andersson, Salix reticulata var. saximontana (Rydb.) Kelso, Salix saximontana Rydb., Salix vestita var. nana Hook.
Family: Salicaceae Mirbel

Syn.: Salvia pseudococcinea Jacq., Horminum coccineum (Buc’hoz ex Etl.) Moench
Family: Lamiaceae Lindl.

Family: Salviniaceae Rchb.

Syn.: Belharnosia canadensis (L.) Nieuwl.
Family: Papaveraceae Juss.

Syn.: Sanguisorba auriculata Scop., Sanguisorba major Gilib., Sanguisorba angustifolia Opiz, Poterium officinale (L.) A. Gray
Family: Rosaceae Juss.

Syn.: Sanicula canadensis var. marilandica (L.) Hitchc.
Family: Apiaceae Lindl.

Syn.: Pterosporopsis sanguinea Kuntze
Family: Ericaceae Juss.; Monotropaceae Nutt.

Syn.: Saururus cernuus f. submersus Gluck
Family: Saururaceae Rich. ex T. Lestib.

Syn.: Hirculus flagellaris Haw., Leptasea flagellaris Small
Family: Saxifragaceae Juss.

Syn.: Saxifraga boryi Boiss. et Heldr., Saxifraga carpathica N. Terracc., nom. illeg., Saxifraga coriophylla Griseb., Saxifraga pseudocaesia Rochel
Family: Saxifragaceae Juss.

Syn.: Micranthes occidentalis (S. Watson) Small, Saxifraga reflexa subsp. occidentalis (S. Watson) Hultén
Family: Saxifragaceae Juss.