The genus Houlletia was established by French botanist Adolphe Théodore (de) Brongniart (1801-1876), who published Houlletia stapeliaeflora (now Houlletia brocklehurstiana in 1841. The genus is named in honor of a French orchid collector in Brazil, M. Houllet, who later became director of the Botanic Jardin des Plantes in Paris. The genus is abbreviated "Hlt."
Photo above, left, taken in Parque Nacional da Tijuca near Rio in March 2008, by Phil Whittman (www.canopyaccess.com).

These are large-growing orchids with 20-25 species, known from Mexico (or possibly Guatemala) through Central and South America, east to the Brazilian Atlantic highlands and south to Bolivia. They are found growing epiphytically and terrestrially on embankments in cool, humid, wet areas, 1,000-2,200 m elevation.

The plants have ovoid, ridged pseudobulbs, each bearing 1-2 large, pleated leaves.
The inflorescences begin from the base of the pseudobulbs and are arching or pendant, with fleshy, showy flowers on a simple raceme. The dorsal sepal is free and the lateral sepals form a short mentum with the column foot. The petals are similar to the dorsal sepal. The lip is deeply 3-lobed, the lateral lobes are upcurved and the midlobe is wide and triangular. The anther contains two waxy pollinia. Dressler (1993a) has a line-drawing of a presumably similar Lacaena pollinarium.

Culture:

Christo Page, Glenstantia, South Africa (January 2001), wrote: "The plant was [grown] in a rockwool/polystyrene mixture in a basket... Temperature is controlled between 13ºC and about 28ºC and humidity stays above about 50% throughout. The plant is watered once a week in summer and once in 10 days during the winter. It gets fertilized with every watering. Once a month clean water is used to flush the growing medium.
"Fairly soon after the magnificent display of flowers which led to it being judged, the plant rapidly declined in health. This necessitated drastic measures of cleaning it from old rotten pseudobulbs and repotting it in a more porous growth medium of about 60% milled polystyrene, 10% perlite and 30% milled rockwool.
"It, therefore, seems as if it is essential to grow Houlletias in a very porous medium or epiphytically while maintaining high humidity in the atmosphere, good air movement and no temperature extremes. A slightly drier regime in winter may also be advantageous. Good quality water is also necessary for soft leaved orchids as they quite easily show chemical leaf burn."

Rand (1876), wrote: "These plants should be grown in well-drained pots, in peat, and need plenty of moisture and frequent watering when in full growth. During the resting season they should be kept in the cold house, nearly dry. The genus seems to be neglected by orchid growers, but for no good reason. All the species are of easy culture, bloom freely, and are very handsome."

Taxonomy:
Gerlach (1999) places the genus Houlletia within the "Acineta-Verwandtschaftsgruppe," allied with Acineta, Lueddemannia, and Vasqueziella within the larger Stanhopinae Alliance.

Whitten, Williams, and Chase distinguish the Houlletia clade among the Stanhopinae, comprising Horichia, Houlletia, Paphinia, Schlimmia, and Trevoria. They write:
"As presently defined, Houlletia consists of two morphologically distinct groups. The ["Euhoulletia" of Schlechter] group containing Hlt. brockelhurstiana (the type species), Hlt. tigrina, Hlt. odoratissima Linden ex Lindl., and Hlt. juruenensis Hoehne have open, resupinate flowers that are heavily spotted in red-brown. The epichile is triangular and the hypochile bears a pair of curved, acute projections; the lip shares many features of the lip of Paphinia. The viscidium is narrow, approximately the same width of the long stipe, and the pollinaria are deposited on the bee's scutellum.

In contrast, the ["Neohoulletia" of Schlechter] group containing Hlt. sanderi, Hlt. wallisii, Hlt. clarae Schltr., and Hlt. lowiana Rchb.f. has globose, nonresupinate flowers that are white to yellow, mostly unspotted, and borne on an erect inflorescence. The epichile is rectangular or ovate (not triangular), and the lateral projections on the hypochile are broad instead of acute. The pollinarium has a broad, concave viscidium."

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Note that in 1999, E. Luckel & H. Fessel published the new genus Jennyella "to accommodate the globose, white flowered taxa." They segregate four species previously attributed to Houlletia into the new genus Jennyella: Hlt. clarae Schlechter 1924; H. kalbreyeriana Kraenzlin 1920; Hlt. lowiana (Rchb. f.); and Hlt. sanderi Rolfe 1910.

In 2007, Szlachetko moved two other species from Houlletia into Jennyella: Hlt. conspersaand Hlt. wallisii.

Awards:
There are eight American Orchid Society awards to four different Houlletia species:
Hlt. lansbergii 'Orchid Art' CHM/83 pts. (now a synonym of Hlt. tigrina).
Hlt. odoratissima 'Esperanza' AM/81 pts.; 'Rolfe' AM/82 pts; 'Merlot Memories' AM/82 pts (+CBM).
Hlt. tigrina (2 HCCs).
Hlt. wallisii 'McHatton-Young' CBR; now Jennyella wallisii
The latest AOS award was granted in June 2001. Oddly enough, there have been no AOS awards to the very handsome type species, Hlt. brocklehurstiana.

Hybrids:
There is one intergeneric hybrid formed with this genus, registered with the RHS in 2000: Houllora (Houlletia Brongn. × Gongora Ruiz & Pav.), abbreviated Hlra.

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The species:

Houlletia brocklehurstiana Brogniart 1841. [Atlantic forest, Brazil]
Rand (1876) wrote: "Perianth richly checkered with brown; lip yellow, marked with purple; very fragrant."

I was lucky enough to have seen hundreds of these plants growing in Tijuca National Park in the hills just inland of Rio de Janeiro, March 2008. Several plants were in bloom, although almost every flower had been chewed by hungry denizens of the forest floor (photo of still-intact buds at right).

Houlletia brocklehurstiana 'Imperial Topaz' AM/SAOC (South African Orchid Council), awarded in March 1997 (ratified October 1999 and chosen as plant of the year by the SAOC).
Awarded to Christo and Aletta Page, Glenstantia, RSA.
Inflorescence was 36.5 cm long, with seven large, fleshy flowers. Horizontal natural spread 8 cm. Flowers are white, creamy brown, and red brown, and the base color of the sepals and petals appears rich topaz. Photo.

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Houlletia chrysantha Linden & Andrae 1871 [Brazil]
in: Ill. Hort. xviii. 138. t. 71.
Rand (1876), writes "A beautiful species, with golden-yellow flowers."

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* Houlletia clarae Schlechter 1924 - now Jennyella clarae
originally published in: Repert. Spec. Nov. Regni Veg. Beih. 27: 81; reclassified by Luckel & Fessel (1999).

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* Houlletia conspersa P. Ortiz 1994 - now [Colombia]
Originally published in: Orquideologia 19(3): 4 (9; fig.); reclassified by Szlachetko (2007).

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Houlletia juruensis Hoehne 1910 [Brazil]
in: Relat. Commiss. Linhas. Telegr. Estrateg. Matto Grosso Amazonas 5, Bot. pt. 1: 47, pl. 38.

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* Houlletia lowiana Linden ex Lindl. & Paxton 1874 - now Jennyella lowiana [Perú and Bolivia]
Originally published in: Gardener's Chronicle & Agricultural Gazette 2: 484; reclassified by Luckel & Fessel (1999).

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Houlletia odoratissima Linden ex Lindley & Paxton 1852-1853 [Panama - Bolivia]
in: Flow. Gard. iii. p. 172.
Rand (1876), writes "A fine species, with orange-brown flowers and white lip." ["New Granada"]
This species has very dark red, glossy sepals and petals and a white lip; it has earned four AOS awards. Chromolithograph at right by L. Stroobant, published 1870 by J. Linden (original dimensions 26.5 cm x 18 cm).

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Houlletia odoratissima var. antioquiensis André 1870 [Colombia]
in: Ill. Hort. 17: 59, tab. 12.
Rand (1876), writes "A variety with blood-red sepals and petals; lip long, white, tinged with yellow."

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Houlletia roraimensis Rolfe 1901 [Venezuela]
in: Trans. Linn. Soc. London, Bot. ser. 2, 6(1):63. [1901-05 publ. Jan 1901]

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* Houlletia sanderi Rolfe 1910 - now Jennyella sanderi [Ecuador]
Photo at right by Ecuagenera. Species was also known as Hlt. elata. Note that lip structure differs greatly from the red spotted species; the epichile is not triangular. In 1999, Luckel & Fessel moved this species into the new genus, Jennyella, named for Swiss botanist and taxonomist Rudolf Jenny.

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Houlletia stapeliiflora Brongn. ex Lem. 1869
in: Ill. Hort. t. 612, in syn.
Rand (1876), writes "Differs but little from Houlletia Brocklehurstiana, of which it is probably a variety."

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Houlletia tigrina Linden ex. Lindl. 1852-53 [Guatemala - western Ecuador]
in: Paxt. Flow. Gard. iii. 171-172.
(syn. landsbergii) The Curtis lithograph at upper right depicts a plant from Costa Rica.
Rand (1876), writes "Flowers yellow and brown; lip white, dotted with brown, and barred with light purple." [Colombia]

This secies has earned two HCC/AOS awards under the name Hlt. tigrina and a CHM/AOS under the synonym Hlt. landsbergii. See lithograph at right - this was published as Hlt. landsbergii. Lithograph below, as well as the stamp issued by Venezuela, shown near the bottom of this webpage.

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Houlletia unguiculata Schlechter 1920
in: Repert. Spec. Nov. Regni Veg. Beih. 7: 160.

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Houlletia vittata Lindl. 1841
in: Edwards's Bot. Reg. 27(Misc.): 47.
Rand (1876), writes "Perianth yellow, striped with brown; lip yellow, striped with orange." [Brazil]

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* Houlletia wallisii Linden & Reichenbach f. 1869 - now Jennyella wallisii [eastern slopes of Andes in Colombia, Ecuador, Peru]
Originally published in: Gard. Chron. 611; reclassified by Szlachetko (2007).
This species has earned a CBR/AOS as Houlletia wallisii.

_____ (2000) Orchid Review 108(1234): New Orchid Hybrids 15. [Lists new intergeneric hybrid, Houllora]

Oakes Ames & D.S. Correll (1985 reprint) Orchids of Guatemala and Belize. New York: Dover Publications Inc., 779 pp. [Lacaena bicolor, pp. 522-524, Fig. 147: line-drawing.]

Adolphe-Théodore Brogniart (1841) "Houlletia brocklehurstiana," in: Annales des Sciences Naturelles; Botanique, sér. 2, 15: 37.

[Bio of Adolphe-Théodore Brongniart: Wikipedia]

Margaret A. Dix and Michael W. Dix (2000) Orchids of Guatemala: A Revised Annotated Checklist. 61p. [p.25: Lacaena bicolor

Robert L. Dressler (1993a) Phylogeny and Classification of the Orchid Family. Portland: Dioscorides Press, 314pp. [p. 175: illustration of Lacaena pollinaria]

Robert L. Dressler (1993b) Field Guide to the Orchids of Costa Rica and Panama. Ithaca: Cornell University Press, 304 pp, 240 illustrations. [p. 149: Lacaena bicolor; L. spectabilis

Guenther Gerlach (2001) "Die Subtribus Stanhopeinae - 3. Horichia bis Lacaena," in: Journal für den Orchideenfreund 8(2): 105-118.

Guenther Gerlach (1999) "80. Subtribus: Stanhopeinae und 81. Subtribus: Coeliopsidinae (Teil 1)," in: Schlechter, Die Orchideen, Band I, Teil C, Lieferung 37/38, 128 p. with 142 B&W illustrations, in German [866. Lacaena, pp. 2429-2431].

Fritz Hamer (22 December 1988) "Orchids of Central America, An Illustrated Field Guide (A-L)," in: Selbyana 10: 1-422. [Line-drawings -- p. 358: L. bicolor and p. 359: L. spectabilis]

"Houllora," (2000) New Orchid Hybrids 15, in: Orchid Review, 108 (1234). [Houlletia x Gongora]

C.H. Lankester (June 1918 and June 1968 reprint) Letter: Orchids of Costa Rica, in: Orchid Review. [Lacaena spectabilis].

Charles Lemaire and Ambroise Verschaffelt (1866-69) "Houlletia tigrina," in: L'Illustration Horticole: Des Serres et des Jardins.

John Lindley (1843) "Lacaena bicolor," in: Botanical Register 29: Misc. 68.

John Lindley (1844) "Lacaena bicolor," in: Edwards' Botanical Register 30: t. 50.

Emil Luckel & Hans Fessel (15 Dec. 1999) "Jennyella, a new genus in the subtribe Stanhopeinae, with notes on the genus Houlletia," in: Caesiana 13: 1-8. [The authors move four Houlletia species into the genus Jennyella: Hlt. clarae (Schltr.); Hlt. kalbreyeriana (Kraenzlin); Hlt. lowiana (Rchb. f.); and Hlt. sanderi (Rolfe)].

Edward Sprague Rand (1876) Orchid Culture. New York: The Rural Publishing. [Orchids. A Description of the Species and Varieties Grown at Glen Ridge... A Complete Manual of Orchid Culture]. Link to this book at the Digital Orchid Library, http://digital.lib.msu.edu/projects/orchids. Houlletia on pp. 291-292: Houlletia Brocklehurstiana, chrysantha, odoratissima, odoratissima antioquiensis, stapeliaeflora, tigrina, vittata.

Gustav Reichenbach (1954) "Lacaena spectabilis," in: Bonplandia, ii. 92.

Schlechter (1915)

Szlachetko (2007) "Jennyella conspersa (P. Ortiz) Szlachetko, comb. nov.," and "Jennyella wallisii (Linden & Rchb.f.) Szlachetko, comb. nov.," in: Polish Botanical Journal: 46-52, p. 34. PDF

W. Mark Whitten, Norris H. Williams, and Mark W. Chase (2000) "Subtribal and generic relationships of Maxillarieae (Orchidaceae) with emphasis on Stanhopeinae: combined molecular evidence," in: American Journal of Botany 87: 1842-1856.
This article distinguishes the two groups of plants attributed to Houlletia at that time: "Euhoulletia," the red spotted group of species with triangular epichiles and "Neohoulletia," the pale yellow to white flowered species with rectangular or ovate epichiles, which Luckel & Fessel had moved into the new genus Jennyella a year earlier (1999).
Available online.

L.O. Williams (1964) "Lacaena nicaraguensis," in: Fieldiana Botany, 31: 41 1964.

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Digital Orchid Library, http://digital.lib.msu.edu/projects/orchids. Houlletia on pp. 291-292: Houlletia Brocklehurstiana, chrysantha, odoratissima, odoratissima antioquiensis, stapeliaeflora, tigrina, vittata.

International Plant Names Index [IPNI], www.ipni.org

Eric Hunt's Houlletia species photos: www.orchidphotos.org. [Hlt. odoritissima, Hlt. tigrina; Hlt. species with pure white lip]

Christo Page (January 2001) "Houlletia" web essay at http://www.ont.co.za/houlletia.htm

Photo of flowering plant of Houlletia tigrina on a Japanese website: http://cospa.main.jp/orchids/Houlletia%20tigrina.JPG

Flora of Panama [MOBOT] - Lacaena spectabilis, Chiriqui Province

Wolfgand Renner's "Orchid Collection", with a photo of L. bicolor.