Voyria images of species A-B, C-M, N-Z 

Common name: Ghostplant (V. aphylla)

Latin name and synonyms: Voyria Aubl., Hist. Pl. Guiane 208 (1775)
Synonym: Leiphaimos Schltdl. & Cham., Linnaea 6: 387 (1831)

Species:  This genus of chlorophyll-less saprophytic plants contains 19 species.

Distribution:  Of the 19 species, all but one occurs in tropical America.  One species, Voyria primulioides, occurs in West Africa.

Habitat:  Tropical rainforest, often in leaf litter on the rainforest floor.

Characteristics:   Perennial, saprophytic herbs, never green, but often white, yellow, pink, purple, or bluish (image). Roots and rhizomes of several types, sometimes coral- or bird's-nest-like (image).  Leaves very reduced, scale-like, sometimes fused at base. Inflorescence terminal, flowers solitary or in larger, cymose inflorescences. Flowers (4–)5(–7)-merous, symmetric, perfect. Calyx (sepals fused) tubular to bell-shaped. Corolla (petals fused at base) trumpet- to funnel-shaped, pink, yellow, white, blue, or purple-colored. Stamens inserted in corolla, sometimes with long, hairy basal appendages (image). Pistil formed from two carpels, with parietal placentation, often with two stalked at the base of the ovary (image). Style long and narrow with various shaped, terminal stigmas. Fruit a dry capsule, sometimes never opening (indehiscent). Seeds minute, many, round to thread-like.

Evolution and related plants:   The Voyria genus is divided into two monophyletic subgenera, subgenus Voyria and subgenus Leiphaimos, based on a phylogenetic study of morphological and anatomical characters (Albert & Struwe, 1997).  These two subgenera differ in many morphological and anatomical characters. Some species show great reduction in features of stem and seed anatomy, lack of stomatas, and embryology (Maas & Ruyters, 1986). Leiphaimos was earlier treated as its own genus, but should be included in Voyria.
      The phylogenetic position of Voyria is uncertain.  Certain characteristics point to a position in/close to Gentianaceae (opposite leaves, hypogynous flowers, no latex, no stipules), but this has yet to be confirmed with DNA sequencing.  Molecular systematics studies has failed due to the apparent lack of chloroplast DNA in Voyria (Struwe & Albert, 2000). In the most recent classification, this genus was therefore classified as 'uncertae sedis', i.e., not put in a tribe at all until more data on its phylogenetic relationships are known.
       Previously Voyria was considered closely related to Voyriella, another gentian saprophyte from South America. However, Voyriella is closely related to genera of the tribe Saccifolieae, and not close to Voyria.

Economic uses:  No economic uses are known.

Notes: Species with larger, round seeds might be dispersed with rainwash, but the more widespread species with filiform, tiny seeds are most likely wind-dispersed.

Accepted/Selected species (synonyms in parenthesis) and their distribution:

References and publications: 

Albert, V. A. & L. Struwe. 1997. Phylogeny and classification of Voyria (saprophytic Gentianaceae). Brittonia 49: 466-479.

Boutique, R. 1972. Gentianaceae. Pp. 1-56. In: P. Bamps, editor. Flore d’Afrique Centrale (Zaire-Ruanda-Burundi). Jardin Botanique National de Belgique, Brussels.

Imhof, S. 1997. Root anatomy and mycotrophy of the achlorophyllous Voyria tenella Hooker (Gentianaceae). Bot. Acta 110: 298-305.

Imhoff, S. 1999. Root morphology, anatomy and mycotrophy of the achlorophyllous Voyria aphylla (Jacq.) Pers. (Gentianaceae). Mycorrhiza 9: 33-39.

Imhof, S. & H. C. Weber. 1997. Root anatomy and mycotrophy (AM) of the achlorophyllous Voyria truncata (Standley) Standley & Steyermark (Gentianaceae). Bot. Acta 110: 127-134.

Imhof, S. & H. C. Weber. 2000. Root structures and mycorrhiza of the achlorophyllous Voyria obconica Progel (Gentianaceae). Symbiosis 29: 201-211.

Maas, P. J. M. & P. Ruyters. 1986. Voyria and Voyriella (saprophytic Gentianaceae). Flora Neotropica Monograph 41. The New York Botanical Garden, Bronx, NY.

Raynal, A. 1967a. Étude critique des genres Voyria et Leiphaimos (Gentianaceae) et révision des Voyria d’Afrique. Adansonia, sér. 2, 7: 53-71.

Struwe, L. & V. A. Albert. 2000a. Mycotrophic, non-chlorophyllous Voyria placed in Gentianaceae. Amer. J. Bot. 87 (suppl.): 161.

Struwe, L., J. W. Kadereit, J. Klackenberg, S. Nilsson, M. Thiv, K. B. von Hagen, & V. A. Albert. 2002. Systematics, character evolution, and biogeography of Gentianaceae, including a new tribal and subtribal classification. Pp. 21-309. In: L. Struwe & V. A. Albert (eds.), Gentianaceae: Systematics and Natural History, Cambridge University Press, Cambridge.

Struwe, L., P. J. M. Maas, O. Pihlar, & V. A. Albert. 1999. Gentianaceae. Pp. 474-542. In: P. E. Berry, K. Yatskievych, & B. K. Holst, editors. Flora of the Venezuelan Guayana, vol. 5. Missouri Botanical Garden, St. Louis. (images)

Links:

Stephan Imhof, The Myco-Heterotrophs-Gallery [saprophytes, images, research]

© Lena Struwe, 2004