oakesia'nus: named for William Oakes (1799-1848), American botanist and lawyer. He was born in Danvers, Mass.,

and entered Harvard in 1816. As a student he developed an interest in natural history under the guidance of his tutor, the noted naturalist and entomologist and the first professor of natural history at Harvard, William Dandridge Peck. After graduation with a B.A. in law in 1820, Oakes studied law with Leverett Saltonstall of Salem, and then, from 1824, began a legal practice in Ipswich, Massachusetts. Oakes eventually gave up law to pursue full-time his interest in natural history, and began to observe and collect plants in Essex County and many other regions of Massachusetts, Vermont, and the White Mts.

Oakes was among the first travelers on a path to the summit of Mount Washington, New Hampshire, that had been constructed in 1821 by the pioneering Ethan Crawford. He came to know Crawford well during his numerous subsequent visits to the White Mountains in which Mount Washington lies. He was asked to contribute a description of White Mountains flora to a geological survey report in 1842 and he expended much energy on this project for the rest of his life. His major work (although not principally a botanical one) was on the scenery of the White Mountains and was published with illustrations by Isaac Sprague soon after Oakes' death in 1848. Having produced a small flora of Vermont, Oakes hoped to complete a flora of New England but was preceded by Lewis Caleb Beck. Much of his rich herbarium was sent to William Sullivant and Edward Tuckerman for study, the latter of whom named the genus Oakesia in his honour.The New England region was his favourite hunting ground and he often travelled alongside Dr. Charles Pickering, coming to know its flora like no other. Oakes drowned on July 31, 1848 after falling off a ferry running between Boston and East Boston. The fungus Aleurodiscus oakesii was named after him by Miles Berkeley and Moses Curtis, and Potamogeton oakesianus (Oakes' pondweed) also bears his name. Others include Oenothera oakesiana and Oakesia conradii, which was later renamed Corema conradii. The writings of Oakes, together with work by Asa Gray, were a significant source for a report produced by George Barrell Emerson in 1846 concerning the trees and shrubs of Massachusetts. The herbarium of the New England Botanical Club holds many specimens collected by Oakes.

obli'qua: lop-sided, oblique, from Latin obliquus "slanting, sidelong, indirect."

obli'ta: forgotten, disregarded, neglected.

oblongifo'lium: with oblong leaves.

Obolar'ia: an obol is a Greek coin, so this epithet means "like a coin" referring to the shape of the leaves, often called pennywort. The genus Obolaria was published by Carl Linnaeus in 1753 and is called pennywort.

obova'lis: same as obovata.

obova'ta: inverted ovate, that is, egg-shaped with the broader end uppermost.

obscur'um: dark, dusky, indistinct, uncertain.

obtu'sa/obtu'sum: blunt, rounded, obtuse, from the Latin obtusus, "blunt."

obtusa'ta: blunted.

obtusifo'lia/obtusifo'lium/obtusifo'lius: obtuse- or blunt-leaved.

occidental'is: from the west, western (compare orientalis, "eastern," borealis, "northern," and australis, "southern")

ochroleu'ca/ochroleu'cum: yellowish-white, buff-colored, the color of the flowers, from the Greek ochro, "yellow-ochre," and leukos, "white, bright."

Ocleme'na: unknown etymology. The genus Oclamena was published in 1903 by Edward Lee Greene and is called whorled aster or nodding aster.

octoflor'a: eight-flowered.

-o'des: like, resembling.

odontorhi'za: from Greek odontos, "a tooth," and rhiza, "root," of unknown applcation.

odora'ta/odora'tus: fragrant, sweet-scented, perfumed.

Oenan'the: wine-fragrant-flower from Greek oinis, "wine." and anthos, "flower, implying that the scent of the flower is like wine (or perhaps suggesting that the smell makes one feel giddy as if from drinking too much wine! The genus Oenanthe was published by Carl Linnaeus in 1753.

Oenother'a: derivation unclear. Several sources say that this name derives from the Greek oinos, "wine," and thera, "to imbibe," because an allied European plant was thought to induce a taste for wine. However, Stearn's Dictionary of Plant Names gives an alternate meaning for thera as "booty," but also suggests that Oenothera could be a corruption of the Greek onotheras from onos, "ass," and thera, "hunting, chase, pursuit" or ther, 'wild beast." Flora of North America says: "Greek oinos, "wine," and thera, "seeking or catching," alluding to roots of some unknown plants possessing perfume of wine, perhaps misapplied by Linnaeus.  The root ther also can have the meaning of "summer." It has been stated as well that the name Oenothera comes from the Greek oinotheras or onotheras for a plant whose roots smell of wine. In Latin, oenothera apparently means "a plant whose juices may cause sleep," and this may be derived from the idea that drinking wine may cause people to be sleepy. What any of this might have to do with the actual plant is unexplained. The genus Oenothera was published by Carl Linnaeus in 1753 in his Species Plantarum and is called evening primrose and sundrops.

officina'le/officina'lis: the word officinalis literally means “of or belonging to an officīna,” the storeroom of a monastery, where medicines and other necessaries were kept. Officīna was a contraction of opificīna, from opifex, “worker, maker, doer,” from opus, “work,” and fex or-ficis, “one who does,” from facere, “to do or perform.” When Linnaeus invented the binomial system of nomenclature, he gave the specific name officinalis, in the 1735 edition of his Systema Naturae, to plants (and sometimes animals) which had an established or supposed medicinal, culinary, or other use.

ohien'sis: of or from Ohio. The species Tradescantia ohiensis is called the Ohio spiderwort.

-o'ides: from the Greek oeides, "like something else," the -oides suffix is usually meant to imply some resemblance and can be attached to a genus name such as Aster (asteroides) or Acrostichum (acrostichoides), or to indicate some resemblance to an object such as drepanoides from the Greek drepane or depranon, "a sickle," thus resembling a sickle.

oklahomen'sis: of or from Oklahoma.

-o'la/o'lus: a diminutive suffix, e.g. Pyrola, a diminutive of Pyrus, not to be confused with -cola.

Oldenland'ia: named for Henrik Bernard Oldenland (1663-1699), a German-born South African physician, botanist, painter and land surveyor. His name is sometimes given as Heinrich Bernhard Oldenland, and he was born in Lubeck on the Baltic coast of northern Germany. Little information has turned up regarding his early life, but he attended Leiden University beginning in 1686 and studied medicine and botany for three years under the influence of Paul Hermann who inspired an interest in botany. He arrived in the Cape Colony in 1688 in the service of the Dutch East India Company, and joined Isaq Schrijver's expedition from January to April 1689. This was the first Cape expedition to penetrate so far into the interior, revealing large numbers of new and interesting plants. In 1690 the Governor of the Cape Colony, Simon van der Stel, recognised Oldenland's training and ability and made him master-gardener and land-surveyor for the colony including becoming superintendent of the botanical garden of the Dutch East India Company with the responsibility for collecting and growing medicinal herbs. Oldenland and his assistant Jan Hartog invested an enormous amount of work in the Company Garden, turning it into an interesting attraction for foreign visitors, and sent seeds of indigenous plants to Paul Hermann. They also worked on a collection of pressed and mounted specimens, including a catalogue of Latin descriptions. Oldenland sent some dried specimens to James Petiver, whose Hortus Siccus Capensis was purchased by Sir Hans Sloane and eventually became part of the founding collections of the British Museum. In 1693 he married Margaretha Hendrina van Otteren. His untimely death at Cape Town in 1697 halted all his botanical work. After his death, Oldenland's collection was seen and admired by many visitors to the Cape, the first to mention it being Peter Kolbe who stayed at the Cape between 1705 and 1713 and published an account of this period in 1719 in Nuremberg entitled Caput Bonae Spei Hodiernum. In the book he lists indigenous and exotic plants growing there, acknowledging his sources as Hartog and the Herbarium vivum of the late Oldenland. The Herbarium vivum was a compilation of pressed useful plants, such as those having, for example, good timber, edible fruits, tubers and corms, often embellished by paintings and sketches, or inked impressions of leaves or flowers. François Valentijn, a Dutch minister and historian, visited the Cape on four occasions between 1685 and 1714, and wrote of seeing 13 or 14 volumes with copious notes in Latin on each plant. He also recorded that the specimens were unusually attractive, exceptionally well dried and expertly mounted. The volumes next came into the possession of Johannes Burmann, then professor of botany at the University of Amsterdam who drew upon the collection for his Thesaurus zeylanicus. Upon his death they passed to his son, Nicolaas Laurens Burmann, who succeeded him as professor of botany. Nicolaas visited Carl Linnaeus, taking along a large collection of Cape plants, including Oldenland's volumes. Linnaeus refers to Oldenland's work in his writings, pointing out that Oldenland was the second trained botanist to collect at the Cape, the first having been Paul Hermann, Oldenland's mentor. In addition to his botanical expertise, Oldenland was a competent draughtsman and may have produced a number of early drawings of Cape plants now in the National Botanical Institute in Pretoria, the British Museum (Natural History), and the Rijksherbarium, Leiden. Furthermore, 24 original drawings of South African Proteaceae that Herman Boerhaave received from Hartog and reproduced in his Index alter plantarum (1720), may also have been made by Oldenland. I have been unable so far to find out anything about the manner of or reason for his early death, but there is little doubt that the Cape floral community was deprived of someone who had a bright future. The genus Oldenlandia was published by Carl Linnaeus in 1753.

olera'cea/olera'ceus: oleraceous, resembling garden herbs or vegetables used in cooking.

oligan'tha/oligan'thus: producing few flowers, from the Greek oligos, "few."

oligocar'pa: with few fruits.

Oligoneur'on: from the Greek oligos, "few," and neuron, "nerve." The genus Oligoneuron was published by John Kunkel Small in 1903.

oligosan'thes: few-flowered, from the Greek oligos, "few," and anthes, "flowering." The species Dichanthelium oligosanthes is called either few-flowered panic grass or Scribner's panic grass, named for Frank L. Scribner (1851-1938), a grass specialist in the U.S. Department of Agriculture.

oliva'cea: greenish-brown, olive-colored, from Latin olivaceus, "olive-green."

oneiden'se: from Oneida County, New York.

Onoc'lea: enclosed cup, this was Dioscorides' name for the sori being concealed by the rolled frond margins. The genus Onoclea was published by Linnaeus in 1753.

Onopor'dum: Gledhill calls it ass-fart, for its flatulent effect on donkeys. The genus Onopordum was published by Carl Linnaeus in 1753.

Onosmo'dium: from onos, "ass," and osme, "odor," and named for likeness to genus Onosma which means "smell of an ass," and to which it is closely related. The genus Onosmodium was published by André Michaux in 1803 and was called false gromwell.

ontario'nis: Wikipedia says: "The species name ontarionis is a Latinization of Ontario for Lake Ontario, as [Karl McKay] Wiegand stated in his description that the species was "apparently limited to the upper St. Lawrence Valley not far from Lake Ontario." The species Symphyotrichum ontarionis is commonly called Ontario aster.

opa'ca: darkened, dull, shady, not glossy or transparent.

ophioglosso'ides: resembling genus Ophioglossum.

Ophioglos'sum: from the Greek ophis, "a snake," and glossa, "a tongue," alluding to the slender fertile leaf spike. The genus Ophioglossum was published in 1753 by Carl Linnaeus.

ophiuro'ides: resembling the genus Ophiurus.

Oplisme'nus: from the Greek hoplismos or hoplismenos, "equipment for war, weapons, armed.". Stearn says "the spikelets of these grasses have awns," and the awns apparently resemble spears. The genus Oplismenus was published by André Michaux in 1803 and is called basketgrass.

-op'sis: a suffix usually indicating resemblance.

opulifo'lium/opulifo'lius: profusely leaved, with leaves like genus Opulus, from the latin opulo, meaning "wealth/profusion," and folium or folius, meaning "leaves."

op'ulus: apparently opulus is a Latin word for a kind of maple. There is a genus Opulus that I assume is from the same derivation. Gledhill says "an old generic name for the guelder rose, Viburnum, originally thought to have been some kind of Acer."

Opun'tia: a Greek name used by Pliny for some plant which grew around the town of Opus in Greece. In 1601 Philemon Holland translated from Pliny's The History of the World, Commonly Called The Natural History of C. Plinius Secundus, "About the city of Opus this an herbe called Opuntia which men delight to eat; this admirable gift the leafe hath, that if it be laid on the ground it will take root and there is no other way to plant the herbe and maintain its kind." Then in 1855, the John Bostock and Henry T. Riley translation of the same passage was "In the vicinity of Opus there grows a plant which is very pleasant eating to man, and the leaf of which, a most singular thing, gives birth to a root by means of which it reproduces itself." Pliny got his information from Theophrastus, and according to David Hollombe, either he was the one who added the name Opuntia or that was added by someone else who copied the manuscript later. The genus Opuntia was published by Philip Miller in 1754 and is called prickly-pear.

Orbex'ilum: this is a genus name for which I can find no information either in print or online. It's amazing that there can be a genus name that nobody knows the meaning of. The only roots that I can find are the Latin orbis, "round, circular, ring" and orbus, "childless, without parents, empty, destitute." The genus Orbexilum is called scurfpea or sampson's-snakeroot, and it was published by Constantine Samuel Rafinesque in 1832, who was notorious for not explaining his choice of names.

orbicula'ta/orbicula'tus: round and flat, disk-shaped.

orienta'le/orienta'lis: eastern. (Compare occidentalis, "western," borealis, "northern," and australis, "southern")

origanifo'lia: with leaves like Origanum.

origano'ides: resembling genus Origanum.

Ori'ganum: the classical Greek name origanon for these aromatic herbs, a name that consists of óros meaning "mountain", and gános meaning "joy", thus, "joy of the mountain". The genus Origanum was published by Carl Linnaeus in 1753.

orizaben'se: from the town of Orizaba, Mexico, and/or from the volcano Citlalpépetl (Pico de Orizaba) in east central Mexico. Its Náhuatl name, Citlaltépetl, comes from citlalli, "star," and tepētl, "mountain" and thus means "Star Mountain". This name is thought to be based on the fact that the snow-covered peak can be seen year round for hundreds of kilometers throughout the region. Rising 18,491', Pico de Orizaba is an active stratovolcano, the highest mountain in Mexico and the third highest in North America, after Denali of Alaska in the United States and Mount Logan of Canada. It is also the highest volcanic summit in North America, and its last eruption was in the 19th century. In 1848 two American soldiers were the first known hikers to reach the summit. The volcano and the area around it were declared in 1936/1937 the Pico de Orizaba National Park. The first collections of the species Galium orizabense were made in this vicinity.

ormosta'chya: from Greek ormos, "a cord, a chain, a nuecklace," and stachys for "ear of grain" or "a spike," the species Carex ormostachys is called spike sedge or necklace spike sedge.

Ornithog'alum: bird's milk. FNA says it derives from the Greek ornis, "bird," and gala, "milk," alluding to the color of the flowers. Wikipedia notes that in some species the flowers look like bird droppings. Another source relates that "The idea of “Bird’s Milk” has come to symbolize something very rare.  The origin of the name has been attributed to old Slavic folk tales, where a beautiful princess tests the ardor and resourcefulness of her suitor by sending him out into the wilderness to find and bring back the one fantastical luxury she does not have: bird's milk." Stearn adds the following: "The bulbs of star-of-Bethlehem (O. umbellatum) are supposed by some to have been the 'dove's dung' of the Bible of which a 'cab' measure was sold for a shekel during the Babylonian siege of Jerusalem." The genus Ornithogalum was published by Carl Linnaeus in 1753 and is called star-of-bethlehem.

Oroban'che: from the Greek orobos, a kind of vetch, and anchone, "choke or strangle" because of a parasitic habit, this was the Greek name of a plant that was parasitic on vetch. The genus Orobanche was published by Carl Linnaeus in 1753 and is called cancer-root or broomrape.

Oron'tium/oron'tium: Stearn says the Greek name orontion, now applied to a North American aquatic, is said to have belonged to some plant in the Syrian river Orontes. The genus contains only a single species, O. aquaticum, which is a native of eastern North America. Common names for it include golden-club, floating arum, never-wet and tawkin. The Orontes River begins in Lebanon and flows northwards through Syria before entering the Mediterranean near Samandağ in Turkey. The genus Orontium was published by Carl Linnaeus in 1753 and is called golden club.

Orthil'ia: from Greek orthos, "straight," and ilium, "side or flank," possibly alluding to secund inflorescence. The Jepson flora says from the Greek: straight spiral, from 1-sided raceme. Common names of Orthilia secunda are sidebells wintergreen and one-sided wintergreen. The genus Orthilia was published by Constantine Samuel Rafinesque in 1840 and is called one-sided shinleaf.

or'um: the suffix -orum usually denotes a place of growth, e.g. desertorum, "of deserts," pinetorum, "of piney woods," tectorum, "of thatched roofs," dumetorum, "of shrubby places," scopulorum, "of cliffs."

Orychophrag'mus: from the Greek oryche, "pit," or orycho, "to dig up," and phragma, "fence or partition," alluding to the minutely pitted septum of the fruit pod. The genus Orychophragmus was published in 1833 by the Russian botanist Alexander Andrejewitsch von Bunge and it is called Chinese violet cress.

Ory'za: Latin oriza and Greek oryza were both names for what we call rice, and probably derived from some Asiatic word. The genus Oryza was published by Carl Linnaeus in 1753.

oryzo'ides: resembling the genus Oryza, which includes rice.

Oryzop'sis: resembling genus Oryza. The genus Oryzopsis was published by André Michaux in 1803 and is called ricegrass.

-osa/-osum/-osus: a Latin adjectival suffix added to a noun indicating an abundance or a marked or full development, e.g. venosus, "full of or marked by an abundance of veins," from vena, "vein"; argillosum, "full of potter's clay" from argilos; also spinosa, ramosa, villosa, dumosa, fruticosa, gloriosa, tomentosa, tuberosa, glandulosa, saxosa, glutinosa, nervosa and others.

Osman'thus: sweet-smelling, fragrant, from Greek osme, "fragrance," and anthos, "a flower." The genus Osmanthus was published by João de Loureiro in 1790 and is called wild olive or devilwood.

Osmun'da: there are two or more possibilities, either for the Anglo-Saxon god of thunder, Osmund, equivalent of the Norse Thor, or for an old English name for Osmund the waterman because of its boggy habitat. There's an English folk tale of a boatman named Osmund hiding his wife and children in a patch of ferns during the Danish invasion. The genus Osmunda was punlished by Linnaeus in 1753.

Osmorhi'za: from the Greek osme, "odor," and rhiza, "root," meaning "odorous root," in reference to the fragrance of the crushed root. The genus Osmorhiza is called sweet cicely and was published by Constantine Samuel Rafinesque in 1819. This is not the only species with the name sweet cicely, and the name apparently comes from the Greek word seselis which was a name given to a group of plants with umbels.

Osmundas'trum: the genus Osmunda and -astrum for "star." The genus Osmunastrum was published by Carl Presl in 1847.

Os'trya: for the Greek name, ostrys, for this species. Gledhill says "hard-scale, a name in Pliny for a tree with hard wood." Flora of North America says "from Greek ostryos, scale, in reference to the scaly infructescences" (fruiting stage of an inflorescence). And SEINet says "Ostrya comes from the Greek name for a different hardwood tree, ostrua, possibly the European hornbeam (Carpinus betulus)." The genus Ostrya was published first by John Hill in 1757 and then by Joannes Antonius Scopoli in 1760, and is called hop-hornbeam and ironwood.

ostryifo'lia: resembling genus Ostrya.

-o'sus: full of, augmented, prone to.

ovalifo'lium/ovalifo'lius: having oval-shaped leaves.

ova'lis: oval, broadly elliptic.

ova'ta: with leaves or some other feature of the plant that are oval- or ovate-shaped.

Oxa'lis: from the Greek oxys for "sharp, sour," referring to the pleasantly sour taste of the leaves and stem. The genus Oxalis was published by Carl Linnaeus in 1753 and is called wood-sorrel or just oxalis.

Oxyden'drum: sour-wood from the Greek oxys, "acid or sour," and dendron, "a tree," alluding to the bitter foliage. The monotypic genus Oxydendrum is called sourwood and was published in 1839 by Augustin Pyramus de Candolle with only a single species, arboreum.

oxylep'is: from Greek oxys, "sharp," and lepis, "a scale," referring to the flower bracts. The species Carex oxylepis is called sharp-scale sedge.

oxyphi'lum: loving acid soil.

Oxyp'olis: another good example of the difficulty of finding out what some of these names mean: Munz says: from the Greek oxys, "sharp," and polis, "city," of uncertain application; while Jepson simply gives the definition as "sharp white." Quattrocchi on the other hand says the name is from "sharp" and polos for "axis or pole," referring to the leaves. The genus Oxypolis has had various names like cowbane, dropwort and hog-fennel, and was published by Constantine Samuel Rafinesque in 1825.

ozarka'nus: of or from the Ozarks. The species Sporobolus ozarkanus is called ozark dropseed.