3,306 articles
Heliconia bihai
Heliconia bihai (macawflower, lobster claw) is a large rhizomatous Heliconiaceae herb native to Mexico, the Caribbean, and northern South America, hummingbird-pollinated, polymorphic in bract color, and cultivated as an ornamental, food, and medicine.
Helictotrichon
Helictotrichon (oat grasses), Poaceae genus published 1827 by Besser ex Schultes & Schult.f.; about 30 accepted species of temperate perennial grasses, narrowed by molecular work, including ornamental blue oat grass H. sempervirens.
Heliotropium
Heliotropium (heliotrope), a genus of about 250 species in Heliotropiaceae (Boraginales) established by Linnaeus in 1753; cosmopolitan herbs and shrubs with scorpioid cymes, pyrrolizidine alkaloids, and C4 species in section Orthostachys.
Heliotropium arborescens
Heliotropium arborescens, garden heliotrope or cherry pie plant (syn. H. peruvianum), is a Boraginaceae subshrub native to Bolivia, Colombia, and Peru, grown for vanilla-scented purple flowers; toxic via pyrrolizidine alkaloids.
Hellebore
Hellebore (Helleborus), also called Christmas rose or Lenten rose, is a genus of about 15 poisonous Ranunculaceae perennials native from Europe to N. China, flowering in late winter and spring, once famed in ancient Greek medicine as a cure for madness.
Helleborus
Helleborus, the hellebores, a genus of about 15-22 poisonous perennial species in Ranunculaceae native from Europe to the Caucasus, NW Africa, and N China; includes the Christmas rose H. niger and Lenten rose H. × hybridus.
Helleborus niger
Helleborus niger, the Christmas rose or black hellebore, is a poisonous Ranunculaceae perennial native to the Alps and Apennines, blooming white December to March, with cardiotonic helleborin and two subspecies, niger and macranthus.
Hemicellulose
Hemicellulose is a group of branched, non-cellulosic polysaccharides in plant cell walls that bind to cellulose and reinforce it, making up 20 to 35% of the wall and including xylans and xyloglucans.
Hemlock woolly adelgid
Hemlock woolly adelgid (Adelges tsugae), a Japanese sap-sucking insect invasive in eastern North America since about 1951, kills eastern and Carolina hemlocks; spread rates, ecology, and chemical and biological control.
Hemp oil
Hemp oil (hemp seed oil) is the culinary oil pressed from Cannabis sativa seeds, naturally free of THC and CBD, GRAS-recognized by FDA in 2018, and distinct from hemp-derived CBD oil extracted from flowers and leaves.
Heracleum (plant)
Heracleum, commonly known as hogweed or cow parsnip, is a genus of about 90 herbs in the carrot family native to the temperate Northern Hemisphere, some reaching 18 ft.
Heracleum mantegazzianum
Heracleum mantegazzianum, giant hogweed, is a 5 m tall monocarpic Apiaceae herb native to the Western Greater Caucasus, invasive in Europe and North America, whose furanocoumarin sap causes phototoxic dermatitis.
Heracleum sphondylium
Heracleum sphondylium, common hogweed or cow parsnip, is a native European Apiaceae herb, 0.3-1.5 m tall with blunt leaves and small umbels, only weakly phototoxic, unlike giant hogweed.
Herb
Herb: botanically, a non-woody plant whose stem dies back yearly; in common use, plants used for flavoring, medicine, and perfume. Key facts: fresh-to-dried ratio 3:1, 0 C storage, USD 5.9 billion fresh herb market.
Herniaria
Herniaria (ruptureworts) is a genus of prostrate Caryophyllaceae herbs published by Linnaeus in 1753, type species H. glabra, with about 52 accepted species from Europe to Central Asia and Africa, traditionally used for hernias and kidney stones.
Hesperis matronalis
Hesperis matronalis, dame's rocket or dame's violet, is a Eurasian biennial mustard with fragrant four-petaled purple or white flowers, widely naturalized and invasive in North America, attacked by the weevil Ceutorhynchus inaffectatus, and often confused with five-petaled garden phlox.
Hesperocyparis
Hesperocyparis (western cypresses) is a Cupressaceae genus published in 2009 for New World species formerly in Cupressus; 17 accepted species, native western North America to Central America, origin ~39.2 Ma.
Heteropogon
Heteropogon (tanglehead) is a genus of about four to six tropical Andropogoneae grasses, type species H. contortus (black speargrass), with twisted hygroscopic awns, pungent calluses, pantropical savanna distribution, and non-monophyletic circumscription.
Heteropogon contortus
Heteropogon contortus (black speargrass, tanglehead, pili grass) is a tufted perennial Poaceae grass of the seasonally dry tropics, a major Queensland pasture grass whose barbed, twisted-awned seeds injure livestock and make it invasive in Florida.
Hevea
Hevea is a genus of ten Euphorbiaceae tree species native to South Tropical America; Hevea brasiliensis, the rubber tree, supplies all commercial natural rubber, used mainly in tires, with guayule and dandelion as alternatives.
Hibiscus
Hibiscus is a genus of about 200–438 species in Malvaceae, tribe Hibisceae, native to tropics and subtropics, known for showy flowers, ornamental and fiber uses, and roselle (H. sabdariffa) tea; molecular studies show the genus is polyphyletic.
Hibiscus syriacus
Hibiscus syriacus, rose of Sharon or shrub althea, is a deciduous Malvaceae shrub native to southern China and Taiwan, the national flower of South Korea, hardy to USDA zone 5, with white-to-purple summer flowers and many cultivars.
Hickory
Hickory (Carya, Juglandaceae): about 16 hardwood species native to Asia, Central America, and North America, prized for shock-resistant tool-handle wood and oil-rich nuts; European species went extinct in the Ice Age.
Hieracium
Hieracium (hawkweeds) is a large Asteraceae genus of perennial herbs with yellow flowerheads, 4,614 accepted species, apomictic polyploids, and a split-off relative genus Pilosella; Mendel's later experimental plant.
High-amylose cornstarch
High-amylose cornstarch (high-amylose maize starch, HAMS, amylomaize starch) is cornstarch with over 50 percent amylose versus 25 to 30 percent normally, from the ae (SBEIIb) mutation; a resistant starch source, GRAS-notified by Yale for oral rehydration solutions at 50 g/L (GRN 000615).
High-fructose corn syrup
High-fructose corn syrup (HFCS), a corn-starch-derived liquid sweetener with 42% or 55% fructose (HFCS-42, HFCS-55), replaced sucrose in most US beverages by the mid-1980s; cheaper than sugar, GRAS status, declining use since 2000.
Hilaria
Hilaria (curly-mesquite, hilaria grass) is a genus of about ten New World grasses in Poaceae, Chloridoideae, subtribe Hilariinae, native from western and central USA to Guatemala, described by Kunth in 1816.
Hippeastrum
Hippeastrum, also called knight's star or horticultural amaryllis, is a genus of about 70-90 bulbous Amaryllidaceae native to Central and South America, sold as Hippeastrum x hybridum, with hollow scapes and papery black seeds.
Hippocrepis
Hippocrepis (horseshoe vetches) is a genus of 34 Fabaceae species in tribe Loteae, native Europe to Pakistan and Macaronesia to Arabia, with curved lomentaceous pods; type-era name from Linnaeus 1753.
Hippophae
Hippophae (sea buckthorn, 沙棘属), spiny dioecious Elaeagnaceae shrubs with seven species from Europe to the Himalaya; H. rhamnoides fixes nitrogen via Frankia and yields vitamin-rich, omega-7 oil berries bred into over 150 cultivars.