Souroubea venosa © Cermeno	Marcgravia brownei © M.T.Schapka
Marcgravia brownei © M. T. Schapke	Marcgravia coriacea © Scott Mori
Marcgravia coriacea © G. Gerlach i	Marcgravia mexicana © R. Aguilar La Selva
Marcgravia stonei © K. Mehltreter	Inflorescence structures A = fertile flower B = nectary C= sterile flower with nectary fused © Stefan Dressler
Mystr_mixtum © Ecuad USoltau	Mystr_subsessile © El Cope
N guian © Holm Nielsen

Contributor

Stefan Dressler

Address

Research Institute Senckenberg, Herbarium Senckenbergianum (FR), Senckenberganlage 25, D-60325 Frankfurt/M., Germany (stefan.dressler@senckenberg.de)

Description

Terrestrial, hemiepiphytic or epiphytic lianas or shrubs, rarely small trees. Roots sometimes adventitious. Hypophyllous glands on the lower surface of the leaf blade, raphide cells and variously shaped sclereids frequent. Leaves simple, alternate, estipulate, glabrous, margins entire or minutely crenate. Inflorescences terminal, racemose, sometimes pseudo-umbels or pseudo-spikes, erect or pendulous. Bracts transformed into variously shaped nectaries. Flowers bisexual, actinomorphic, hypogynous, 2-bracteolate, the bracteoles sepaloid or deltoid, sometimes lacking. Sepals 4-5, unequal, free or nearly so, imbricate, persistent. Petals 3-5, imbricate, free or connate. Stamens 3 to many; filaments free or basally connate, uniseriate; anthers basifixed or nearly so, dithecal, tetrasporangiate, introrse, longitudinally dehiscent. Ovary superior, completely or incompletely 2-20-locular; ovules numerous. Fruits subglobose, apiculate with a persistent style and stigma, capsular, loculicidally and septifragously dehiscent from the base (sometimes appearing berry-like), pulpy inside. Seeds hemispherical to reniform, few to numerous with a shiny reticulate testa.

Notes on delimitation

2 subfamilies:
Marcgravioideae: Leaves distichous; conspicuos heterophylly between juvenile, plagiotropous and adult, orthotropous branches; Perianth tetramerous, petals fully fused to form a caducous cap; only central (sterile) flowers of inflorescence fused with nectary bract, other flowers lacking nectary. (Marcgravia)

Noranteoideae: Leaves spiral; Perianth usually pentamerous, petals distinct to somewhat fused; each flower usually subtended by nectary bract.  (all other genera)

Vegetatively similar to the Ternstroemiaceae (non-climbing!) this family was formerly considered to be close to Theaceae/Ternstroemiaceae. Recent molecular data associate it rather with Balsaminaceae, and the former Theaceae-satellites Pellicieraceae and Tetrameristaceae.

Distribution in Neotropics

Endemic to Neotropics. Species range from Southern Mexico to Northern Bolivia and Eastern Brazil including the Antillean arc.

Marcgraviastrum, Souroubea, Norantea, and Sarcopera species are missing on the Antilles (but Norantea guianensis being rarely cultivated as an ornamental).

Taxa are mostly found in primary humid tropical lowland forests or montane rain or cloud forests.

Number of genera

Marcgravia (ca. 65 spp.): S Mexico, Mesoamerica, South America, Antilles,
Marcgraviastrum (15 spp.): S Nicaragua to Peru, Bolivia plus 2 spp. in E Brazil
Norantea (2 spp.): Caribbean and Amazonian basin of NE South America
Ruyschia (9 spp.): Mesoamerica, N Andes, Lesser Antilles
Sarcopera (ca. 10 spp.): Honduras to N Bolivia, Guyayana Highlands
Schwartzia (ca. 15 spp.): Costa Rica through the Andes south to Bolivia, in the Caribbean basin and 1 sp. in E Brazil
Souroubea (19 spp.): Mexico to Bolivia (absent from the Antilles)

Status

Native and endemic to the Neotropics, Norantea guianensis sometimes cultivated in countries outside its range (e.g. Jamaica, Costa Rica, Trinidad).

Key differences from similar families

Flower bracts with extrafloral nectaries turned into conspicuous “nectar-containers” in each inflorescence.

Leaves with (vestigial) extrafloral nectary glands on lower surface.

Climbing habit.

Fruit capsular with seeds embedded in fleshy pulp.

Distinguishing characters (always present)

Woody plants.
* Bracts with extrafloral nectaries turned into variously shaped nectar-containers.
* Terminal inflorescences: racemes, umbels or spikes.
* Leaves alternate and simple with abaxial glands.
* Fruit capsular with seeds embedded in fleshy pulp.

Other important characters

* usually climbing
* often hemiepiphytic
* youngest leaf enclosing the terminal bud
* young growth often reddish coloured by anthocyans
* flowers with variously connate petals
* stamens 3 or 5 or many

Useful tips for generic identification

Key to the genera

1. Inflorescence umbellate or subumbellate. 2.
1*. Inflorescence spicate or racemose. 3.

2. Inflorescence completely fertile; sepals and petals 5; petals free or variously connate; leaves spirally arranged. 6. Marcgraviastrum
2*. Inflorescence partly sterile (central flowers aborted with only the bracteal nectaries developed); sepals and petals 4; petals calyptrately connate; leaves distichously arranged. 7. Marcgravia

3. Inflorescence spicate; nectaries attached to the rachis next to the flowers. 5. Sarcopera
3*. Inflorescence racemose; nectaries variously attached to the pedicel.

4. Stamens 3-5, rarely 4 or 6-8; nectaries attached to the pedicel at the base of the calyx, rarely at some distance. 5.
4*. Stamens (5-)12-35(-80); nectaries attached to the pedicel at various distances from the calyx, but never at its base. 6.

5. Ovary 2-locular; nectaries gibbose or somewhat leaf-like, solid or nearly so. 1. Ruyschia
5*. Ovary 3-5-locular; nectaries tubular, hollow, often auriculate. 2. Souroubea

6. Inflorescence an elongated raceme, 25-60(-85) cm; pedicels 2-5(-7) mm); nectaries adnate above the middle of the pedicel, never attached at the base. 3. Norantea
6*. Inflorescence a short raceme, 4-25(-35) cm; pedicels (20-)30-70 mm; nectaries adnate below the middle of the pedicel, rarely at the base. 4. Schwartzia

Notable genera and distinguishing features

See Image: Inflorescence structures

General notes

The elaborate inflorescences with the variously shaped bracteal “nectary-containers” are visited by a wide range of visitors (insects, lizards, birds, bats, non-flying mammals). Different pollination syndromes are exemplified in the various taxa. Wheras Ruyschia and Souroubea seem predominantly insect-pollinated (flies?, butterflies, hawk-moths?), Norantea, Sarcopera and Schwartzia brasiliensis are probably best adapted to bird-pollination, especially by perching birds. Sarcopera sessiliflora was the first plant where pollen transmission by bird´s feet was described. Most Schwartzia, Marcgraviastrum and Marcgravia spp. seem to be mostly bat-pollinated, but the ornithophilous syndrome seems to occur as well. This is a coarse generalisation and surprisingly many Marcgraviaceae are probably autogamous as well (and even cleistogamous, as experimentally proven in Marcgravia coriacea.)

The brightly coloured pulp with the small seeds exposed when the capsules split open suggest endozoochorous dispersal.

Apart from occasional horticultural use in the tropics the family has no significant economic value.

Important literature

The elaborate inflorescences with the variously shaped bracteal “nectary-containers” are visited by a wide range of visitors (insects, lizards, birds, bats, non-flying mammals). Different pollination syndromes are exemplified in the various taxa. Wheras Ruyschia and Souroubea seem predominantly insect-pollinated (flies?, butterflies, hawk-moths?), Norantea, Sarcopera and are probably best adapted to bird-pollination, especially by perching birds. Sarcopera sessiliflora was the first plant where pollen transmission by bird´s feet was described. Most Schwartzia, Marcgraviastrum and Marcgravia spp. seem to be mostly bat-pollinated, but the ornithophilous syndrome seems to occur as well. This is a coarse generalisation and surprisingly many Marcgraviaceae are probably autogamous as well (and even cleistogamous, as experimentally proven in Marcgravia coriacea.)

The brightly coloured pulp with the small seeds exposed when the capsules split open suggest endozoochorous dispersal.

Apart from occasional horticultural use in the tropics the family has no significant economic value.