Neotropical Balanophoraceae

Piero G. Delprete

Institut de Recherche pour le Développement (IRD), France; Herbier de Guyane, IRD, French Guiana, France. 

Description

Herbaceous, fleshy plants, entirely or partially subterraneous, "fungus-like", parasitic on roots of trees, shrubs or herbs, without chlorophyll, without stomata, with white, yellow, red or brown color; "tuber" (undefined root/stem structure) branched, unbranched, globose, or irregularly shaped, with the inflorescence originating directly from the "tuber ". Leaves reduced to scales, spirally arranged, margin entire, venation not evident. Inflorescence spicate or spadix-shaped, the lateral branches much reduced or absent; bracts scale-like, triangular, ovate, hexagonal or almost round, peltate. Flowers unisexual. Male flowers 3-merous, with 3-lobed perianth, or a synandrium of 3 free anthers; anthers 2(3)-locular, basifixed, opening by longitudinal slit. Female flowers with a 2-lobed or irregularly-lobed perianth, or absent; ovary inferior; ovary without well-defined locules, placenta, and ovules; styles 1 or 2, stigma minutely capitate. Fruit a minute, 1-seeded achene.

Distribution in the Neotropics

  • Corynaea Hook.f. (1 sp.): Panama, Colombia, Venezuela, Ecuador, Peru, and Bolivia.
  • Helosis Rich. (1 sp.): Mexico, Central America, Greater Antilles, Colombia, Ecuador, Peru, Bolivia, Venezuela, Guianas, throughout southern Brazil.
  • Langsdorffia Mart. (1 sp.): Throughout the Neotropics, from Mexico to southern Brazil.
  • Lathrophytum Eichl. (1 sp.): Brazil (states of Goiás and Rio de Janeiro).
  • Lophophytum Schott & Endl. (4 spp.): Colombia, Peru, Bolivia, Brazil, Paraguay, and northern Argentina.
  • Ombrophytum Poepp. ex Endl. (4 spp.): Ecuador, Galapagos Islands, Peru, Bolivia, Brazil, Chile, and Argentina.
  • Scybalium Schott & Endl. (4 spp.): Greater Antilles, Colombia, Venezuela, Ecuador, and Brazil.

Distinguishing characters (always present)

  • Parasitic plants, on roots trees, shrubs or herbs.
  • Entirely or partially subterraneous.
  • Without chlorophyll.
  • Without stomata.
  • White, yellow, red or brown color.
  • "Tuber" branched, unbranched, globose, or irregularly shaped.
  • Inflorescence originating directly from the "tuber ".
  • Flowers minute, unisexual,: male flowers 3-merous, female flowers 2-merous.
  • Ovary without well-defined locules, placenta, and ovules.
  • Fruit a minute, 1-seeded achene.

Key differences from similar families

  • Family very distinctive from other parasitic taxa, by its set of unique characters.
  • The other family of subterranean holoparasitic root parasites with subterranean habit is the Hydnoraceae, which is a characterized by a large, fleshy, solitary flower, with 3-4 fleshy tepals, and a large fruit with numerous seeds.

Number of genera

Worldwide 18 genera and 45 species. In the Neotropics, 7 genera and 16 species:

  • Corynaea (1 sp.)
  • Helosis (1 sp.)
  • Langsdorffia (1 sp)
  • Lathrophytum (1 sp.)
  • Lophophytum (4 spp.)
  • Ombrophytum (4 spp.)
  • Scybalium (4 spp.)

Useful tips for generic identification

Key to genera of Neotropical Balanophoraceae

Key adapted from Hansen (1980):

1. Style 1; tubers with wax; flowers not embedded in filiform hairs, or anthers 3, merged into a synandrium ... Langsdorffia
1. Styles 2; tubers with starch; flowers with both sexes imbedded in filiform hairs, or anthers 2, not merged into a synandrium ... 2 

2. Flowers embedded in a layer of filiform hairs; anthers merged into a usually 3-merous  synandrium ... 3
2. Flowers not imbedded in hairs, on conspicuous or elongated branches, these subtended by deciduous scale-like bracts; stamens with filaments ... 5

3. Stem and young inflorescence covered by triangular scales ... Scybalium
3. Stem naked, or with a few inconspicuous bracts; young inflorescence covered by hexagonal, peltate bracts ... 4 

4. Inflorescence emerging from buds on elongated, rhizome-like structures, these appearing from a "tuber" connected with the host root... Helosis
4. Inflorescence emerging directly from a "tuber" connected with the host root... Corynaea

5. Inflorescence branches subtended by ovate -triangular bracts; apical part of female branch not peltately enlarged ... Lophophytum
5. Inflorescence branches subtended by hexagonal or irregularly-shaped bracts; apical part of female branch peltately enlarged, covering the flowers ... 6  

6. Male flowers solitary, each flower subtended by a peltate bract; anthers sessile... Lathrophytum
6. Male flowers in many-flowered branches, these subtended by a peltate or clavate bract; stamens with evident filaments ... Ombrophytum

Notable genera and distinguishing features

See above

Status

  • A poorly known family in terms of distribution, pollination, and number of species, mostly due to their partially or entirely subterranean habit.
  • Some reports of plants visited by flies, bees and wasps, but no definitive studies about their pollination biology. Also, some reports about seed dispersal by ants.
  • Their general physiology is also little-known, as is a family without stomata.

Important literature

Borchsenius, F. & , J.M. Olesen. 1990. The Amazonian root holoparasite Lophophytum mirabile (Balanophoraceae) and its pollinators and herbivores. J. Trop. Ecol. 6: 501-505.

Delprete, P.G. 2004. A new species of Lophophytum and the first report of Lathrophytum (Balanophoraceae) from the state of Goiás, Central Brazil. Kew Bull. 59: 291-295.

Hansen, B. 1980. Balanophoraceae. Fl. Neotrop. Monogr. 23: 1-80.

Kuijt, J. & W.X. Dong. 1990. Surface features of the leaves of Balanophoraceae - A family without stomata? Pl. Syst. Evol. 170: 29-35.

How to cite

Delprete, P.G. (2009). Neotropical Balanophoraceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Balanophoraceae.htm.