The Curious Plant that Looks like a Fungus

Posted June 23, 2022

In May we continue our exploration in the Reserva de Biósfera Maya (RBM). We had the opportunity to visit the "Multiple Use Zone" where the forestry concessions are located, we focus mainly on “La Gloria” concession. Among the most interesting plant species that we found was the genus Helosis, since at first glance it looks like a fungus. But then we realize it was actually a plant because we have documented it previously in Sayaxche, Petén.

Why does it look like a fungus?

Balanophoraceae is a family of 17 genera of holoparasitic geophytes, that means, a plant that takes all its nutrients from the host plant because it does not have chlorophyll in its tissues. It has roots characterized by an aberrant vegetative and underground body, without leaves, stems or roots, called tuber, which may have rhizome-like branches. These parasitic plants attach to the root of host shrubs and trees of dark tropical forest species. The inflorescences are the only aerial part of the plant and several of them can appear along the rhizomes, making it difficult or impossible to define an individual. A peculiarity of the inflorescences is their endogenous origin (in relation to their own tissues), a unique characteristic in angiosperms. Its flowers are minute and a wide range of extreme reductions can be observed between genera, especially in female flowers and similarly in its seeds, with embryos consisting of few cells (Hansen, 1980; Kuijt, 1969; Mauseth, Hsiao & Montenegro, 1992, Heide, 2008; Su, Hu, Anderson, Der & Nickrent, 2015).

Helosis is one of the genera of the Balanophoraceae family It includes three species, the recently discovered H. antillensis, H. ruficeps and H. cayennensis, that has two varieties: var. cayennensis and var. Mexicana (Gonzalez, Sato & Marazzi, 2019)

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Helosis cayennensis being pollinated by Trigona fulviventris. La Gloria forest concession, Reserva de Biósfera Maya (RBM) May, 2022. Photograph by Edwin Solares

Botanical Information:

It has light brown tubers, irregular, with a rough surface, about 20 to 35 mm long by 20-30 mm wide and no more than 20 mm high, located about 5 cm deep. The rhizomes are 4-5 mm in diameter, light brown, branched, aphyllous, arranged parallel to the surface, about 5-7 cm deep. they form a network that begins in the tubers and on them the flower stems are formed. The stems of the underground system are cylindrical, solid, and measure up to 18 cm in height and 1.5 cm in diameter. The base of the peduncle is ring-shaped with bracts 2-5 mm high, welded at their bases and with irregular triangular ends. The inflorescence rises at the end of the floral peduncle, it is an oval spadix that in the adult state reaches about 2.5 to 3 cm wide and up to 5-6 cm long, it is covered by capitate bracts, hexagonal in tangential view, deciduous, 2.5mm wide by 5.5mm high (Fontana & Popoff. 2006).

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Measures of Helosis cayennensis. La Gloria forest concession, Reserva de Biósfera Maya (RBM) May, 2022. Photograph by Edwin Solares.

Phenology: Most of the year the plant is reduced to its underground organs. It parasitizes fine and medium roots (the thickest root was 5 mm in diameter). In November and December, the inflorescences begin to appear on the surface, initially in the form of a small head that blends in with the litter and, as it develops, becomes light brown with the central part of the bracts somewhat darker. The flower stalk begins to grow and raises the inflorescence above the soil surface to a height of 15-18 cm (Fontana & Popoff. 2006).

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Helosis cayennensis. La Gloria forest concession, Reserva de Biósfera Maya (RBM) May, 2022. Photograph by Edwin Solares.

Bibliography

• FONTANA, F. and POPOFF, O.
• 2006
• Helosis (Balanophoraceae) en Argentina. Bol. Soc. Argent. Bot. 41 (1-2): 85 - 90
  
  Available Online:
  www.scielo.org.ar/pdf/bsab/v41n1-2/v41n1-2a07.pdf

• GONZALEZ, A. M., SATO, H. A. and B. MARAZZI
• 2019
• Embryology in Helosis cayennensis (Balanophoraceae): Structure of Female Flowers, Fruit, Endosperm and Embryo. Plants 2019, 8 (3), 74.
  
  Available Online:
  www.mdpi.com/2223-7747/8/3/74/htm#B5-plants-08-00074

• HANSEN, B.
• 1980
• Balanophoraceae. Flora Neotrop. Monogr. 1980, 23, 1–80.

• HEIDE, H.S.
• 2008
• Parasitic Flowering Plants; Koninklijke Brill Academic Publishers: Leiden, The Netherlands.

• KUIJT, J.
• 1969
• The Biology of Parasitic Flowering Plants; University of California Press: Berkeley, CA, USA.

• MAUSETH, J.D.; HSIAO, S.C. and G. MONTENEGRO
• 1992
• Vegetative body of the parasitic angiosperm Helosis cayennensis (Balanoporaceae). Bull. Torrey Bot. Club, 119, 407–417.

• SHU-Chan, J. D. and L. D. GOMEZ
• 1993
• Growth and Anatomy of the Vegetative Body of the Parasitic Angiosperm Helosis cayennensis (Balanophoraceae). Bulletin of the Torrey Botanical Club Vol. 120, No. 3, pp. 295-309

• SU, H., HU, J., ANDERSON, F. E., DER, J. P. Der and NICKRENT, D. L.
• 2015
• Phylogenetic relationships of Santalales with insights into the origins of holoparasitic Balanophoraceae. Taxon, 64, 491–506.

Written by Eng. Vivian Hurtado & Eng. Victor Mendoza