Plants — 23,508 Species

Black Tupelo

Nyssa sylvatica Marshall

Nyssa sylvatica Marshall, the black tupelo, is a long-lived North American deciduous tree valued for its brilliant autumn color.

pennywort

Obolaria virginica L.

Obolaria virginica, or Virginia pennywort, is a small perennial mycoheterotrophic flowering plant native to eastern US forests.

hammock fern

Oceaniopteris cartilaginea (Sw.) Gasper & Salino

Oceaniopteris cartilaginea, the gristle or soft water fern, is a resilient fern native to eastern Australian forests.

showy plane

Ochna natalitia (Meisn.) Walp.

peeling plane

Ochna pulchra Hook.

Ochna pulchra Hook. is a distinctively barked African tree that indicates Gifveld containing toxic Dichapetalum cymosum.

Small-leaved plane

Ochna serrulata (Hochst.) Walp.

Ochna serrulata is a South African native shrub cultivated ornamentally that has become a weed in parts of Australia.

Balsa Tree

Ochroma pyramidale (Cav.) Urb.

Ochroma pyramidale, commonly called balsa, is a fast-growing American tree famous for its soft, lightweight commercial wood with many uses.

whorled wood aster

Oclemena acuminata (Michx.) Greene

Oclemena acuminata is a perennial herb native to eastern North America that can hybridize with Oclemena nemoralis to form Blake's aster.

bog aster

Oclemena nemoralis (Aiton) Greene

Oclemena nemoralis is a perennial herb native to northeastern North America, growing in acidic bogs across most of its range.

Pinebarren Aster

Oclemena reticulata (Pursh) G.L.Nesom

Oclemena reticulata is a perennial herbaceous flowering plant native to the southeastern United States.

Yellow Odontites

Odontites luteus (L.) Clairv.

Odontites luteus is an annual hemiparasitic yellow-flowered plant found in Europe and North Africa, growing in sunny, dry habitats.

Red Bartsia

Odontites vernus (Bellardi) Dumort.

Red bartsia (Odontites vernus) is a partial parasitic wildflower native to Eurasia, considered a weed in parts of Canada.

Red Odontites

Odontites vulgaris Moench

Odontites vulgaris is a flowering plant in Orobanchaceae native from Europe to Siberia and China.

Cardinal’s guard

Odontonema cuspidatum (Nees) Kuntze

Odontonema cuspidatum is an Acanthaceae plant species endemic to Mexico that has been introduced to multiple other regions.

Firespike

Odontonema tubaeforme (Bertol.) Kuntze

Odontonema tubaeforme is an upright ornamental shrub native to Central America that is invasive in parts of the Pacific.

Fairy Fern

Odontosoria chinensis (L.) J.Sm.

Odontosoria chinensis, commonly lace fern, is a Lindsaeaceae fern native to tropical and subtropical regions with historical Hawaiian uses.

Square Perdekaroo

Oedera squarrosa (L.) Anderb. & K.Bremer

Oedera squarrosa is a small South African shrublet with dense small leaves and yellow spring-summer flowerheads.

Osoberry

Oemleria cerasiformis (Torr. & A.Gray ex Hook. & Arn.) J.W.Landon

Oemleria cerasiformis is a dioecious deciduous shrub native to Pacific North America, used by Native American tribes.

Fine-leaved Water-dropwort

Oenanthe aquatica (L.) Poir.

Oenanthe aquatica, or fine-leaved water-dropwort, is a wetland umbellifer herb native to Eurasia.

Hemlock Water-dropwort

Oenanthe crocata L.

Oenanthe crocata (hemlock water-dropwort) is a toxic European perennial wetland plant linked to the ancient 'sardonic grin'.

Java water-dropwort

Oenanthe javanica (Blume) DC.

Oenanthe javanica is an edible perennial herb that is officially invasive in several U.S. states.

Corky-fruited Water-dropwort

Oenanthe pimpinelloides L.

Oenanthe pimpinelloides (corky-fruited water-dropwort) is a European perennial umbellifer that can be weedy outside its native range and is eaten locally in Turkey.

water parsley

Oenanthe sarmentosa C.Presl ex DC.

Oenanthe sarmentosa, commonly water parsley, is a North American wetland perennial Apiaceae that can become an introduced noxious weed.

Oenothera affinis Cambess.

Oenothera affinis Cambess.