Seed plants

Rudbeckia hirta

Rudbeckia hirta, black-eyed Susan or gloriosa daisy, is a North American Asteraceae forb, annual to short-lived perennial, with yellow ray flowers and a dark cone; Maryland's state flower since 1918, with four varieties and many cultivars.

Rudbeckia laciniata

Rudbeckia laciniata, cutleaf coneflower or sochan, a North American perennial Asteraceae with cut leaves, edible young leaves, livestock toxicity, and invasive status in Europe and Japan.

Ruellia

Ruellia (wild petunia), a large genus of Acanthaceae flowering plants published by Linnaeus in 1753, with about 375-388 species native to tropics, subtropics, and North America; type species Ruellia tuberosa.

Rumex

Rumex (docks and sorrels) is a genus of about 200 Polygonaceae herbs with six-part flowers, accrescent inner perianth valves, and trigonous nuts; some dioecious species have heteromorphic sex chromosomes.

Rumex crispus

Rumex crispus (curly dock, yellow dock) is a perennial Polygonaceae herb native to temperate Eurasia and now a global weed; about 224 phytochemicals, traditional laxative and astringent uses, oxalate and emodin toxicity.

Rumex obtusifolius

Rumex obtusifolius, broad-leaved dock or bitter dock, a perennial Polygonaceae weed native to Europe to Central Siberia and Iran, invasive in pastures worldwide; up to 60,000 seeds yearly, oxalic acid, controlled via Pyropteron biocontrol.

Runcaria

Runcaria, scientifically Runcaria heinzelinii, is a fossil plant reproductive structure from Middle Devonian Belgium, about 385 million years old, and the earliest known evidence of the seed habit.

Ruppia

Ruppia (widgeon grass, ditch-grass) is the sole genus of Ruppiaceae, submerged brackish-water monocots with hydrophilous pollination, cosmopolitan distribution, salinity tolerance from freshwater to hypersaline, and disputed species limits (4-12 species).

Ruppia maritima

Ruppia maritima, commonly called beaked tasselweed or wigeongrass, is a cosmopolitan submerged aquatic flowering plant of brackish and saline lagoons, ponds, salt marshes, and coastal pools.

Ruscus aculeatus

Ruscus aculeatus (butcher's broom, Rusci rhizoma) is an evergreen Asparagaceae shrub whose leaf-like cladodes are modified stems. Its rhizome, standardized to ruscogenins, holds an EMA traditional-use monograph for heavy legs and hemorrhoid symptoms.

Ruta

Ruta (rue) is a genus of about 12 aromatic Rutaceae herbs native to Macaronesia and the Mediterranean, best known for Ruta graveolens, a medicinal herb with furanocoumarin-related phototoxicity.

Ruta graveolens

Ruta graveolens, common rue, is an aromatic Rutaceae subshrub native from the N. Balkan Peninsula to Crimea, cultivated as a medicinal herb; furanocoumarins make it phototoxic and abortifacient.

Rutaceae

Rutaceae, the rue or citrus family (Rutaceae Juss., 1789), is a Sapindales family of 161 genera and 2,070 species of aromatic trees, shrubs and lianas with pellucid oil glands, including Citrus, Pilocarpus, and Zanthoxylum.

Rye

Rye (Secale cereale) is a winter-hardy cereal grain, a secondary domesticate from a weed of wheat and barley fields, dominant in medieval Germany from about 1000 CE; today the EU grows 68.4 percent of world output, used for bread, feed, spirits, and cover cropping.

Sabal

Sabal (palmettos), genus of New World fan palms described by Adanson in 1763; about 15 species from the southeastern USA, Caribbean, Bermuda, and Central America, defined by costapalmate fronds, unarmed petioles, and split leaf bases.

Sabal palmetto

Sabal palmetto, the cabbage palmetto or cabbage palm, is an unbranched southeastern US palm, state tree of Florida and South Carolina, hardy to about 15°F, with an edible terminal bud and high hurricane wind resistance.

Sabatia

Sabatia Adans. (rose gentian, marsh-pink) is a genus of 21 Gentianaceae herb species native from southeastern Canada to Mexico and the Caribbean, named for Italian botanist Liberato Sabbati, published 1763.

Saccharum

Saccharum is the Poaceae grass genus holding sugarcane; 15 accepted species native from Central and East Asia to the Old World tropics and Australia; modern cultivars are S. officinarum x S. spontaneum hybrids with an 8.7-billion-base, 114-chromosome genome.

Saccharum officinarum

Saccharum officinarum, the noble cane or sugarcane, is a tropical grass (2n=80) domesticated from S. robustum in New Guinea about 8,000 years ago; it supplies about 80% of modern hybrid cultivar genomes and most of the world's sugar.

Saccharum spontaneum

Saccharum spontaneum (wild sugarcane, Kans grass, Canne Dauvage) is a rhizomatous Old World tropical grass, wild progenitor contributing 15-20% of modern sugarcane genomes, an invasive weed in Panama, and a bioenergy feedstock.

Safflower

Safflower (Carthamus tinctorius), also called false saffron, is a thistle-like annual of the daisy family grown for its edible oil and historically for its red and yellow dyes.

Sage

Sage (Salvia, Lamiaceae), a genus of about 1,000 aromatic mint-family species worldwide, known for lever pollination, culinary garden sage (Salvia officinalis), chia, and controversial polyphyletic taxonomy.

Sagina (organism)

Sagina (pearlwort), a genus of small Caryophyllaceae herbs named by Linnaeus in 1753, type S. procumbens; about 30-37 species, mainly north-temperate and arctic; includes horticultural Irish/Scotch moss (S. subulata).

Sagittaria

Sagittaria (arrowhead, duck potato) is a cosmopolitan genus of aquatic Alismataceae herbs published by Linnaeus in 1753, type S. sagittifolia, with sagittate leaves, unisexual whorled white flowers, edible tubers, and a South American origin.

Sago

Sago (Metroxylon sagu, rumbia): starch from the trunk of a swamp-adapted Southeast Asian palm, a staple food in eastern Indonesia and Papua; yields up to 25 t/ha, harvested after 8-12 years, with food and industrial uses.

Saguaro

Saguaro (Carnegiea gigantea, O'odham Ha:san), giant columnar cactus of the Sonoran Desert; grows only there, lives 150-175 years, reaches 50 feet, fruits used by Tohono O'odham.

Salacca

Salacca is a genus of about 23 spiny, understory Arecaceae palms native from the eastern Himalaya to western Malesia; it includes Salacca zalacca, the salak or snake fruit palm, and differs from relatives like Eleiodoxa by scaly, tart edible drupes.

Salak

Salak (Salacca zalacca), snake fruit, she pi guo, is a dioecious Indonesian palm native to Java and Sumatra, grown for scaly snake-skin fruit; Central Java leads production and Bali's Karangasem salak agroforestry is a FAO heritage system.

Salicaceae

Salicaceae, the willow family (Salix, Populus), is a family of about 54 genera and over 1,400 species of trees and shrubs in the order Malpighiales, expanded from two genera to include former Flacourtiaceae, with major timber and environmental uses.