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, densely caepitose 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 in the summer and fall on 1 to several apical, distichous to subsecund, densly and simultaneously many tiny flowered racemes that are much longer than the leaf with a tubular, as long as the ovary floral bract.
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 Crocodeilanthe spiralis (Lindl.) Toscano 2018; 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 ;
Edwards's Bot. Reg. 21: t. 1797 Lindley 1835 as Physosiphon spiralis;
Orchidées 32-33: f. 44-53 De Puydt 1880 an nom. valid.? as P clasusa;
Gen. Sp. Orchid. 2: 94. Barb. Rodr. 1881 as Stelis deregularis;
Fl. Bras. 3(4): 341-342. [Barb. Rodr.] Cogn 1896 as Physosiphon deregularis;
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;
Anexos Mem. Inst. Butantan, Secç. Bot. 1(4): 38 Schlechter 1922 as Pseudostelis bradei;
Anexos Mem. Inst. Butantan, Secç. Bot. 1(4): 38 Schlechter 1922 as Pseudostelis deregulais; Anexos Mem. Inst. Butantan, Secç. Bot. 1(4): 38 Schlechter 1922 as Pseudostelis spiralis
Schedul. Orchid. 8: 11 Schweinfurth 1925 as Physosiphon minutiflorus;
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;
Ceiba 5: 92 L O Williams 1956 as P schweinfurthiana;
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;
Icones Pleurothallidinarum Vol III Systematics of PleurothallisLuer 1986;
Icones Pleurothallidinarum Vol III Systematics of Pleurothallis Luer 1986 as P pichinchae;
Icones Pleurothallidinarum Vol III Systematics of Pleurothallis Luer 1986as P velaticaulis;
