Pleurothallis deregularis (Barb. Rodr.) Luer 1978 SUBGENUS Pseudostelis
Photos by Luis Filipe Varella and his Flickr Orchid Photo Website
TYPE Drawing by Martius, Eichler and Urban: "Flora Brasiliensis" vol. 3 pt. 4 tab. 78.
Drawing by Carl Luer
and 
Common Name The Irregular Pleurothallis
Flower Size .2" [5 mm]
Found from Belize, Honduras, Costa Rica, Panama and then Ecuador, Peru and Brazil in lowland forests at elevations of 100 to 1900 meters as a small to medium sized, densly caespitose, hot to warm growing epiphytic herb with clustered ramicauls enveloped basally by 2 to 4 tubular sheaths and carrying a single, apical, coriaceous to subcoriaceous, erect to patent, variable, lanceolate, oblong, elliptic, oblanceolate-ligulate, to ovate, obtuse to rounded apically, from almost sessile to cuneate to longly attenuate and petiolate base leaf that blooms on 1 to several apical, distichous to subsecund, densly and simultaneously many tiny flowered racemes that are much longer than the leaf, that occurs in the summer and fall.
This species superficially resembles a Stelis but the sepals are simple and connate basally, the petals are minute, membraneous and single veined if at all, and the transverse lip is obscurely tri-lobed in varying proportions with suberect, obtuse sides or lateral lobes and a similar apical lobe. There are no calli but the narrowly concave base is below a transverse callus that is firmly attached to the tip of the column foot." Luer 1999
Synonyms Physosiphon deregularis (Barb. Rodr.) Cogn. 1896; Physosiphon minutiflorus Ames & C. Schweinf. 1925; Physosiphon spiralis Lindl. 1830; Pleurothallis clausa A. Rich. ex Rchb. f. 1857; Pseudostelis bradei Schltr. 1922; Pseudostelis deregularis (Barb. Rodr.) Schltr. 1922; Pseudostelis schweinforthiana L.O. Williams ; Pseudostelis spiralis (Lindl.) Schltr. 1922; *Stelis deregularis Barb. Rodr. 1882;
References W3 Tropicos, Kew Monocot list , IPNI ; Symbolae Antillanae Vol VI Orchidaceae Urban 1909 as P crassipes; Symbolae Antillanae Vol VI Orchidaceae Urban 1909 as P velaticaulis; Die Orchideen Schlechter 1915 as Physosiphon deregularis; The Orchids of Panama L.O. Williams & P Allen 1946 as Physosiphon minutiflorus drawing good; Iconografia de Orchidaceae Do Brasil Hoehne 1949 as Psuedostelis bradei drawing fide; Iconografia de Orchidaceae Do Brasil Hoehne 1949 drawing fide; Venezuelan Orchids Vol 2 Dunsterville & Garay 1961 as P velaticaulis; Encyclopedia of Cultivated Orchids Hawkes 1965 as Pseudostelis bradei; Encyclopedia of Cultivated Orchids Hawkes 1965 as Pseudostelis derregularis; Flora de Venezuela Foldats Volumen XV Part 2 1969 as Pleurothallis velaticaulis; Orchidaceae Brasilense Band 1 Pabst & Dungs 1975 as Physosiphon deregularis drawing ok; Orchidaceae Brasilense Band 1 Pabst & Dungs 1975 as Physosiphon spiralis drawing ok; Icones Planetarum Tropicarum plate 139 Dodson 1980 as Physosiphon spiralis drawing ok; Icones Planetarum Tropicarum plate 224 Dodson 1980 drawing fide; Systematics of Pleurothallis Vol 3 Luer 1986; Systematics of Pleurothallis Vol 3 Luer 1986 as P pichinchae; Systematics of Pleurothallis Vol 3 Luer 1986 as P velaticaulis; Icones Pleurothallidinarum Vol XVIII Systematics of Pleurothallis subsection Antenniferae, Longiracemosae, Macrophyllae-Racemosae and Subgenera Pseudsostelis and Acuminata Luer 1999 drawing fide; Lindleyana Vol 16 No 4 2001 as Stelis velaticaulis; Manual de Plantas de Costa Rica Vol 3 Hammel, Grayum, Herrera and Zamora 2003; Orchidees du Bresil As Orquideas da Serra do Castelo [Espirito Santo Brazil] Chiron & Bolsanello Vol 2 2013 as S deregularis drawing fide/photo good
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