Epidendrum denticulatum

Taxobox
name = "Epidendrum denticulatum"
regnum = Plantae
divisio = Magnoliophyta
classis = Liliopsida
ordo = Orchidales
familia = Orchidaceae
genus = "Epidendrum"
species = "E. denticulatum"
binomial = "Epidendrum denticulatum"
binomial_authority = Barb. Rodr.

"Epidendrum denticulatum", one of the crucifix orchids, is a reed stemmed species which, at least in herbarium specimens, is frequently confused with "E. secundum" Jacq. Like "E. secundum", the flowers of "E. denticulatum" are non-resupinate and are born in a congested racime at the end of a long spike. Like all crucifix orchids, the lip is adnate to the column and bears three lobes, producing the effect of a cross.

Distinguishing Characteristics

Perhaps the most noticeable difference between "E. denticulatum" and "E. secundum" is the callus: "E. denticulatum has two small calli near the collumn and a long keel beginning between them; "E. secundum" has a single, much larger callus in front of the collumn.

To assist in distinguishing herbarium specimens, Pinheiro and Barros undertook a statistical examination of flowers growing under cultivation in Sao Paulo, Brazil. They found that "E. denticulatum" had column length of 7-8 mm, and a labellum (lip) with a width of 11.7-13.4mm, a lateral lobe length of 4.9-5.7 mm (measured from the edge of the callus to the end of the lateral lobe), and a central lobe length of 2.2-3.2 mm (from the point where the lateral and central lobes meet), as opposed to "E. secundum", which had a comumn length of 4.7 - 6.2 mm, and a lip with a width of 8.6-7.2 mm, a lateral lobe length of 2.5-3.8 mm, and a central lobe length of 3-4 mm.

According to Almeida & Figueiredo, "E. denticulatum" Jacq. produces nectar "on the petioles of buds, flowers, and fruits," but not on the flowers. According to Pansarin & Amaral, "E. secundum" has a nectary at the back of the tube formed by the flower lip and column.

Occurrence

"Epidendrum denticulatum" occurs in Espirito Santo (among other states), Brazil, at altitudes of about 1 km.

Sources

*Almeida, A. M., and Figueiredo, R. A.: "Ants vist nectaries of Epidendrum denticulatum (Orchidaceae) in a Brazilian rainforest: effects on herbivory and pollination" Brazilian Journal of Biology 634 (Nov. 2003).
*Pansarin, E. R., and Amaral, M. C. E.: "Reproductive biology and pollination mechanisms of "Epidendrum secundum" (Orchidaceae). Floral variation: a consequence of natural hybridization?" Plant Biology 10 (2008) 211-219.
*Pinheiro, F., and Barros, F.: "Epidendrum secundum" Jacq. e "E. denticulatum" Barb. Rodr. (Orchidaceae): caracteres uteil para a sua delimitacao" 34(4):563-570, 2007.