1. Orchidaceae Juss.

    1. This family is accepted.

[FWTA]
Habit
Perennial, terrestrial, epiphytic or saprophytic herbs with rhizomes or tuberous roots or rootstock; stem leafy or scapose, frequently thickened at the base into pseudobulbs and bearing aerial assimilating roots
Leaves
Leaves undivided, alternate and often distichous, rarely opposite, sometimes all reduced to scales, often fleshy, sheathing at the base
Flowers
Flowers bracteate, hermaphrodite or very rarely polygamous or monoecious, zygomorphic; inflorescence spicate, racemose or paniculate, or flowers solitary
Perianth
Perianth epigynous, composed of 6 petaloid segments (tepals) in 2 whorls, or the outer whorl calyx-like and the inner corolla-like, or the outer rarely corolla-like and the inner minute, free or variously connate in each whorl; outer segments (sepals) imbricate or subvalvate, the middle segments of each whorl generally different in size and colour from the lateral ones, especially the middle petal which is often extremely complicated in structure and is termed the lip or labellum; the basal part of the labellum, the hypochile, is often articulated to the base of the column or is much constricted, when it is termed the claw; the middle part, the mesochile and the apical part, the epichile, may be variously lobed and often bear outgrowths. On account of the twisting of the ovary through 180°, the labellum is often placed in an abaxial position; frequently the labellum or more rarely the odd sepal is prolonged into a sac or spur, sometimes very long
Androecium
Stamens 2 or 1; stamens and style united to form a special structure (column), the apex of which may be produced vertically into stelidia or laterally into wings, and the base of which may be produced downwards to form a foot; anther or anthers 2-locular, introrse, opening by a slit lengthwise; often operculate, i$e$ can be lifted like a little cap; pollen granular or generally agglutinated into mealy, waxy or bony masses (pollinia); at one end the pollinium may be extended into a sterile portion (caudicle); the pollinia may be free in the anther-loculi or more or less loosely united
Gynoecium
Ovules very numerous and minute Ovary inferior, 1-locular with 3 parietal placentas or very rarely 3-locular with axile placentas, usually produced at the apex to form the column; stigmas 3 fertile, or more frequently the lateral 2 fertile, the other sterile and transformed into a small outgrowth (rostellum) which lies between the anther and the stigmas; a portion of the rostellum is sometimes modified into a viscid disk or disks (viscidia) to which the pollinia are attached, often by a stalk or stipes
Fruits
Fruit usually a capsule, mostly opening laterally by 3 or 6 longitudinal slits
Seeds
Seeds very numerous, minute, often drawn out at each end, or rarely winged, without endosperm; embryo not differentiated
[FTEA]
Habit
Perennial, terrestrial, saprophytic, epiphytic or very rarely subterranean or aquatic herbs or rarely scramblers, with rhizomes, tubers or rootstocks with mycorrhizal fungi in the roots and usually elsewhere
Growth
Growth usually sympodial, occasionally monopodial
Stem
Stems usually leafy, but leaves often reduced to bract-like sheathing scales, one or more internodes at or near the base frequently variously swollen into a “pseudobulb”; those of epiphytic species often bearing aerial assimilating roots protected from excessive heat and water-loss by layers of dead cells called the velamen
Leaves
Leaves rarely hairy, undivided except at apex in some cases, alternate or very occasionally opposite, often distichous, frequently fleshy and often terete or canaliculate, almost always with a basal sheath which frequently surrounds the base of the peduncle, sometimes articulated at base of lamina and sometimes with a false petiole
Inflorescences
Inflorescence spicate, racemose or paniculate, terminal and/or axillary, the flowers rarely secundly or distichously arranged, or flowers solitary
Flowers
Flowers bracteate, hermaphrodite or very rarely polygamous or monoecious, zygomorphic, sessile or variously pedicellate, most often twisted through 180° (resupinate), occasionally not twisted or twisted through 360°
Perianth
Mentum or chin frequently formed from lateral sepals where tepals join column-foot The segments of the outer whorl and 2 lateral segments of the inner whorl termed tepals, especially when basically similar in size, shape and colour Median segment of inner whorl almost always markedly different from the 2 lateral segments Median segment of outer whorl (“dorsal” sepal) often different in size and shape from the 2 laterals, sometimes saccate or with 1 or 2 spurs Perianth epigynous; perianth-segments 6, usually free but less frequently variously adnate, connate or adherent to one another or to the column, arranged in 2 whorls; both whorls similar or outer whorl (sepals) calyx-like and inner (petals) corolla-like, or outer whorl corolla-like and inner very reduced Median segment of inner whorl (lip or labellum) entire or variously lobed, frequently laciniate or fimbriate, often brightly coloured and frequently spotted or otherwise ornamented, often bearing crests (keels or carinae) along its length or with central portion (disk) or throat bearing a callus or cushion of hairs, often produced backwards into a sac or spur (rarely 2) up to 30 cm. long and sometimes with nectar at apex; often differentiated into 2 or 3 parts: basal part termed hypochile, often hinged to base of column or narrowed into a claw; middle part termed mesochile; apical part termed epichile
Androecium
Anthers attached by their bases or apices, opening by a slit lengthwise or often operculate; pollen in distinct tetrads, sticky or agglutinated into 2, 4, 6 or 8 pollinia; pollinia mealy, waxy or horny masses, often divided into a number of smaller portions (sectile); at one end each pollinium occasionally drawn out into a sterile caudicle Stamens 1, 2 or 3, ± united with the style to form a special organ termed the column (gynostegium), apical part of which may be produced laterally into wings or vertically into stelidia, basal part often produced downwards to form a column-foot The whole structure of pollinia, stipes or caudicle and viscidium form the pollinarium
Gynoecium
Ovary inferior, 1-locular with 3 parietal placentas or rarely 3-locular with axile placentation, produced at the apex to form the column; very rarely apex of ovary with ring-like outgrowth (calyculus); ovules very small and numerous Stigmas 3, fertile or more usually the 2 lateral ones fertile and the other transformed into an outgrowth (rostellum) lying between the anther and the lateral stigmas; part of the rostellum often modified into a sticky disk or disks called viscidia to which the pollinia are attached by 1 or 2 stalks (stipes) also derived from rostellum or by the sterile caudicle
Fruits
Fruit a capsule opening laterally by 3 or 6 longitudinal slits
Seeds
Seeds very numerous and small, without endosperm and with an undifferentiated embryo, often markedly winged
[FZ]
Habit
Growth either sympodial or less commonly monopodial Perennial, terrestrial, saprophytic or epiphytic herbs or rarely scrambling climbers, with rhizomes, root-stem tuberoids or rootstocks with mycorrhizal fungi in the roots and often elsewhere
Stem
Stems usually leafy, but leaves often reduced to bract-like scales, one or more internodes at the base often swollen to form a pseudobulb; aerial, assimilating adventitious roots, often bearing one or more layers of dead cells called a velamen, are borne in epiphytic species
Leaves
Leaves glabrous or occasionally hairy, entire except at the apex in some cases, alternate or occasionally opposite, often distichous, frequently fleshy and often terete or canaliculate, almost always with a basal sheath which frequently sheaths the stem, sometimes articulated at the base of the lamina and sometimes with a false petiole
Inflorescences
Inflorescences erect to pendent, spicate, racemose or paniculate, one to many-flowered, basal, lateral or terminal, the flowers rarely secund or distichously arranged
Flowers
Flowers small to large, often quite showy, hermaphrodite or rarely monoecious and polymorphic, sessile or variously pedicellate, most often twisted through 180 degrees, occasionally not twisted or twisted through 360 degrees
Gynoecium
Ovary inferior, unilocular and the placentation parietal, or rarely trilocular and the placentation axile Stylar and filamentous tissue forming a long or short column, with or without a basal foot, occasionally winged or with lobes or arms at apex or ventrally; anther one (or rarely two or three in extra African taxa), terminal or ventral on column, with a concave anther cap or opening by longitudinal slits; pollen in tetrads, agglutinated into discrete masses called pollinia; pollinia mealy, waxy or horny, sectile or not, 2, 4, 6 or 8, sessile or attached by caudicles, a stipes or stipites to one or two sticky viscidia; stigma 3-lobed, the mid-lobe often modified to form a rostellum, the other lobes either sunken on the ventral surface of the column behind the anther or with two lobes porrect
Perianth
Perianth epigynous, of two whorls of three segments; outer perianth whorl (sepals) usually free but sometimes variously adnate, the median (dorsal) often dissimilar to the laterals, the laterals sometimes adnate to the column foot to form a saccate, conical or spur-like mentum; inner whorl comprising two lateral petals and a median lip; petals free or rarely partly adnate to sepals, similar to sepals or not, often showy; lip entire, variously lobed or two or three-partite, ornamented or not with calli, ridges, hair cushions or crests, with or without a basal spur or nectary, margins entire to laciniate
Fruits
Fruit a capsule, opening laterally by 3 or 6 slits; seeds numerous, dust-like, lacking endosperm, sometimes markedly winged

Images

Orchidaceae Juss. appears in other Kew resources:

First published in Gen. Pl. [Jussieu] 64. 1789 [4 Aug 1789]

Accepted in:

  • [1] APG IV (2016) http://dx.doi.org/10.1111/boj.12385

Sources

Flora of Tropical East Africa
[A] http://creativecommons.org/licenses/by-nc-sa/3.0

Flora of West Tropical Africa
[B] http://creativecommons.org/licenses/by-nc-sa/3.0

Flora Zambesiaca
[C] http://creativecommons.org/licenses/by-nc-sa/3.0

International Plant Names Index
The International Plant Names Index (2016). Published on the Internet http://www.ipni.org
[D] © Copyright 2016 International Plant Names Index. https://creativecommons.org/licenses/by/3.0

World Checklist of Selected Plant Families
World Checklist of Selected Plant Families(2016). Published on the Internet http://apps.kew.org/wcsp/
[E] © Copyright 2016 International Plant Names Index and World Checkist of Selected Plant Families. https://creativecommons.org/licenses/by/3.0