A BRIEF REVIEW OF THE ORCHID FLORA OF PUERTO RICO
Moderator: Jose Izquierdo
January 17 & 24, 2001

Please note that the picture links are from webpages which OrchidSafari has no control over, so some links may end up broken if the owners of those images change their locations on the web. We are sorry for that inconvenience. The source of each photo is cited via its URL. We owe many thanks to Jay Pfahl's wonderful page The Orchid Species Encyclopedia.

A detailed list of the Orchid Flora of Puerto Rico has been placed in this archive for you to download and here is a Map of Puerto Rico and the Virgin Islands.

As you can see from the map I provided, the island of Puerto Rico is basically rectangular in shape with dimensions of approximately 175 km in length (109 miles) and 60 km in width (37 miles) and, covers an area of 8497 sq km (3280 sq mi) making it the smallest of the 4 main islands that make up the Greater Antilles.

To its West there are some small-uninhabited islands the largest of them being Isla de Mona (known as a landing point for illegal immigrants, drug smugglers, great hunting, fishing, scuba diving and, home to some Orchids). To the South (and along the Southern coast) there are numerous small cays that support mostly vegetation composed of various mangrove species. To the East there are the Island Municipalities of Vieques (134 sq mi) and Culebra (26 sq mi) and the islands that make up the US and British Virgin Islands. (Vieques is the home to a US Naval target range which for the last 60 years the US navy has used to practice with live ammunition some of them containing depleted uranium and the home for various Orchid species including an endemic color form of Psychillis macconnelliae.) To the North and all along the coast, lies the Atlantic Ocean.

Puerto Rico and the Virgin Islands (with the exception of St Croix) were connected as a single landmass during the Pleistocene and form a single geographical unit known as Greater Puerto Rico; a cohesive bio-geographic unit as almost all of the species that occur in the Virgin Islands also occur in Puerto Rico.

Puerto Rico is a geological diverse island and could be as well divided in 3 distinctive physiographic areas:

• The coastal lowlands: extensive; surrounds most of the island and is geologically and ecologically heterogeneous. (The little "bottle neck" described in the map is the only area that has no significant coastal low lands).
• The limestone karst region that cover an extensive area of the Northern and some of the Southwest and South-Central parts of Puerto Rico. In the Northern karst region, differential weathering has created a series of complex systems of caves, sinkholes and, haystack hills known in Puerto Rico as mogotes. It is in one of those mogotes that the dish for the Arecibo Radio Telescope is located. [We are talking a big hole.] The Southern karst region is less diverse and doesn't support a mogote system.
• The uplands are composed of two distinct mountain regions: in the Northeast corner the Luquillo Mountains whose tallest peak El Yunque) reaches 1000 meters and the Cordillera Central (with its eastern extension, the Sierra de Cayey) forms a central backbone to the Island. Its highest peak, Cerro de Punta towers about 1338m or 4389 ft and is located on the Northern boundary of my hometown, Ponce. The predominant soil type of the Southwestern mountain areas is serpentine, a soil type that allows for very fast drainage of area after heavy rains.

For many of you that live in places that have HUGE mountains these uplands may seem like hills at best, speed bumps. Remember the scale we are talking about: El Yunque goes to 1000 meters from sea level in less than 3 miles and Cerro Punta goes from bellow sea level to 1338 m in less than 12 miles; the slopes are impressive and the effects on weather is awesome. The effect of El Yunque on the air mass of hurricanes is known… Hugo was shoved more than 1 degree of latitude North, allowing PR to escape the brunt of its maximum winds and changing its path to the route that took it to North Carolina. The mountain ranges of PR serve as a moisture barrier and are in part responsible for the huge precipitation differences in the PR land area (From 300+ inches a year near el Yunque, on the NE to less than 1 inch of rain per year in the extreme SW corner of PR)

Greater Puerto Rico has a tropical oceanic climate dominated by easterly trade winds. Here is a great explanation of the tropical weather pattern in the Caribbean Area.

The rainfall season is throughout the year with a relative dry season from December to April. With the exception of hurricane season (August - November) when rain falls occur in long and violent downpours, the rainfall pattern in Puerto Rico is generally one of brief, sometimes intense, local showers. The distribution of rainfall is highly dependent on the topography with the result of a variety of locally variable climates thorough the island.

Let us view some statistics and numbers:

Rainfall: Maximum is approx 4500 mm + of rain per year in the NE corner of PR at the Yunque (That is about 178 to 250 inches a year). In the central regions the average rainfall range is 1500-2500 mm a year (59-99 inches), in the Southeast, the average rainfall is 950 mm a year (37 inches); while in the South west the rainfall averages about 250 mm in my town
(Ponce) dwindling down to less than 25 mm a year (less than 1 inch) in the SW corner.

Temperature: Mean annual temperature in the mountains is 18.4 C
(~65F), 27.5 C in the South (~81.5F) while the North, the average temperature is about 10 C less with mean minimums of 21C (69.8F) and mean highs of 31C(88F). Highest recorded temperature in PR is 104 F
(40C), the lowest is 6C (42.8F). Our cold season is in winter: December to February.

Here is a good review of climate and tropical climate zones in general.

A person flying over Puerto Rico may be impressed by an apparent abundance of forestland since our current forest cover is between 45-50% of our total surface area. But that figure is misleading if we take into account that in Pre-Colombian times the forest cover was greater than 98%. By the early 1900's the de-forestation rate was of more than 75% of the surface land area. It is in the mid 1940's that the deforestation trend is reversed. (Sadly the development policies of our last governor lead to an increase of deforestation that threatened the habitat of many sensitive / threatened species.) I know this is a talk about Orchids but those who believe in habitat conservation must be vigilant of government development policies that do not take in consideration the ecological well-being of A nation.

Thus, most of Puerto Rico's forests are second growth forests. If they give the appearance of older growth it is because of the effect if the destructive forces of hurricanes which maintain Puerto Rico in a state of relative lack of vegetative equilibrium. Puerto Rico gets hit on the average every 5 to 10 years by a really destructive hurricane.

For brevity purposes, I will only mention the Main Ecological Zones found in Puerto Rico [Classification is based on the Holdrige Scale/System.]. If you want more information on them please email me.

• -Subtropical Moist Forest (2 variants: in the karst area and in the serpentine soil area).
• -Subtropical Dry Forest
• -Subtropical Wet Forest (2 variants: in the karst area and in the serpentine soil area)
• -Subtropical Rain Forest
• -Subtropical Lower Montane Wet Forest
• -Cloud/Elfin or Dwarf forest
• -Palm Brake

It can be said that, Greater Puerto Rico shows a great variation in climate and life zones. [Please remember the scale in which this is happening.]

The Holdridge System takes only temperature over land and precipitation and ignores important factors as rates of evaporation, air mass movement, water currents and temperature, intensity of sunlight per unit area.

It is estimated that there are about 150 species validly annotated for Greater Puerto Rico. You were provided a list of those plants, a list of the species that have escaped from cultivation and have established themselves in natural settings, a list of all the species annotated for Puerto Rico at one time or another but are considered not valid at this time and, a list which presents a classification scheme of those species.

Before we continue, let us remember that when we are dealing with a compilation of the work of several scientists some questions arise regarding the correctness of those compilations and their completeness. Among them:

• - Scientific validity: some annotations of species have no scientific validity as they record an artificial introduction of the species and not the introduction and establishment of the species in nature. An example of this is the annotation of Cattleya labiata for Puerto Rico by Cogniaux and Urban (1903) "Quasi spontanea ad arbores vetustas prope Ponce" ["appearing spontaneously in trees in the City of Ponce."]. This annotation doesn't reflect the natural introduction of the species in PR but the custom in PR of tying Orchids to trees.
  
• - Escape from cultivation: 6 species annotated as found in Greater Puerto Rico are the result of escape from cultivation and successful adaptation in nature: Vanilla pompona, Vanilla planifolia, Phaius tancarvillae, Spathoglottis plicata, Arundina gramminofolia and, Epidendrum radicans. [Note there is a hybrid of Vanilla also escaped into cultivation]

  My spelling of Phaius tancarvillae follows that in taxonomical literature.

• - Changes in nomenclature: The example of this sequence shows how some names get to be excluded as they no longer considered valid: Epidendrum cochleatum > Encyclia cochelata > Annacheilum cochleatum > Prostechea cochleata.
  
• - Re-designation of species: In the case of the species of Greater Puerto Rico we have witnessed the reclassification and re-designation of various species: Examples: Leochilus labiatus segregated to yield Leochilus puertoricensis; Epidendrum boricuarum segregated from Epidendrum difforme.
  
• - Recognition that species have been misidentified: the species described for Greater Puerto Rico as Encyclia biffida is actually Psychillis macconnelliae.
  
• - Lack of agreement between authorities, Ex: Onc. altissimum Vs Onc. wylderi
  Can you notice any difference?
• - Lack of publication of annotation Ex: Tetramicra elegans
  
• - Destruction of natural habitat: Ex: Brassavola nodosa
  The destruction of the habitat of Brassavola nodosa and its removal from the listing of native species was a gradual one: It was the end result of more than 150 years of deforestation and urbanization of the habitat. More sudden and more painful have been the disappearance of Galeandra beyrichii (due to the stealing of the only member of population from natural habitat) and Cranichis ricartii (Due to the dynamiting of the location where both populations that had been recorded existed to pave way for an unnecessary road.).
  
• - Ambiguity in the description and annotation
  
• - Variability of species: Ex: Tolumnia varriegata

The following 16 species are considered to be endemic to Greater Puerto Rico:

Brachionidium ciliolatum Garay RARE
Chranichis ricartii Ackerman VERY RARE BELIEVED EXTINCT
Epidendrum boricuarum Hágaster & Sanchez SCATTERED/COMMON
Leochilus puertoricensis Mchase UNCOMMON
Lepanthes carithensis Tremblay & Ackerman CRITICALLY ENDANGERED
Lepanthes dodiana Stimson UNCOMMON
Lepanthes eltorensis Stimson RARE/ENDANGERED
Lepanthes rubripetala Stimson UNCOMMON
Lepanthes rupestris Stimson LOCALLY COMMON
Lepanthes selenipetala Reicnenbach f UNCOMMON
Lepanthes veleziana Stimson LOCALLY COMMON
Lepanthes woodburyana Stimson COMMON
Psychilis kraenezlinii (Bello) Sauleda UNCOMMON
Psychilis krugii (Bello) Sauleda LOCALLY COMMON
Psychilis monensis Sauleda LOCALLY COMMON
Tolumnia prionochilia (Kraenzlin) Braem LOCALLY COMMON

Greater Puerto Rico is biogeographically cohesive with the Greater Antilles. With the exception of the 16 endemics and 7 other species annotated for Greater Puerto Rico, ALL other orchids occur on at least one other island of the Greater Antilles. There are 342 Orchid Species annotated for the Greater Antilles (Bahamas and Florida included) of those 11 occur throughout the West Indies, and only 5 are strictly associated with the Lesser Antilles. Of the species annotated for Greater Puerto Rico some 58 are restricted to the West Indies, 86 are distributed at least through Mexico Central or South America (of those 86 at least half occur throughout the American Tropics. One species, Oeceoclades maculata, is pan tropical.

The 150 or so species annotated for Greater Puerto Rico are distributed among 63 genera.

James Ackerman, PhD is recognized as the taxonomic authority on Orchid species native to Puerto Rico. [Here is a small biography with address and short list of publications ]

Eurystyles ananassocomos, Galeandra beyrichii, Koellensteinia graminea, Malaxis major, Malaxis spicata, Pleurothallis obovata.

• - Rarity, not necessarily horticultural desirable, small in size (flower and plant)
  
• - Deforestation: natural, man made (urbanization land development, agriculture land use and practice)

These pictures give an indication of the variety of Orchid flora in Greater Puerto Rico. They also show the close biological relationship between the land masses of tropical and semi tropical America:

Encyclia gravida (Lindley) Schlecter. For those of you who have never seen a herbarium sheet with all annotations made. A picture of this species can be found under the name Epidendrum oncinoides.

Lets us continue with the 16 species considered ENDEMIC TO PUERTO RICO.

Brachionidium ciliolatum Garay
SUBFAMILY Epidendroideae, TRIBE Epidendreae, SUBTRIBE Pleurothallidinae. This species has been collected only in the elfin forest at the high latitudes of the Luquillo Mountains (Map reference the area where towns 60, 15, 52 and 43 meet) Some people argue this is not an endemic species but it is actually Brachionidium dusssi (Native of Guadeloupe.) I was not able to obtain a picture or line drawing.

Chranichis ricartii Ackerman This is a sad case. One of the most recently discovered species. The total population of this little terrestrial herb found in one of the forests of the town of Maricao (Map reference 47) found its way in the path of progress and its location was blown up to pave way for the road. The search for surviving individuals continues so its status is very rare/probably extinct. I was able to obtain a line drawing. Please observe the dimension references in drawing.

Epidendrum boricuarum Hágsater & Sanchez

This scattered and common species was segregated from what Hágaster calls the "Epidendrum difforme complex". Honestly, I cannot see a difference between flowers.

Leochilus puertoricensis MChase
This Oncidium relative is not common in Puerto Rico where it has been collected near the wards of Rio Grande (Map Reference 60). It has been confused with Leochilus labiatus.

Lepanthes carithensis Tremblay & Ackerman

This species is considered CRITICALLY ENDANGERED (IUCN RED LIST STATUS). In a previous OS I mentioned the facts that have resulted in this condition (none of them man made)

Lepanthes dodiana Stimson,
Lepanthes eltorensis Stimson,
Lepanthes rubripetala Stimson,
Lepanthes rupestris Stimson,
Lepanthes selenipetala Reicnenbach f,
Lepanthes veleziana Stimson,
Lepanthes woodburyana Stimson,

In the absence of pictures I am including a key to the species involved with its descriptions. And the following line drawings: [AGAIN NOTICE THE SCALE REFERENCES]

[Drawing #1] [Drawing #2] [Drawing #3] [Drawing #4]

Psychilis kraenzlinii (Bello) Sauleda - Rare. Grows in the Western Central towns of Maricao and Yauco and in the Northwest "corner" of Puerto Rico. Lithophytes some are epiphytic. Likes shadier and moister conditions than krugii or monensis. AOS has awarded 3: 'Cupo' that got an HCC (and a CCC for owner) [AQ 26, p64]; 'Juan Ramirez' AM/AOS [AQ 21 p 92]; 'Laura Teresa', CBR/AOS (AQ20, 193]

The natural hybrid Psychilis x raganii [Psychilis (kraenzlinii x krugii)] is similar in shape to this plant but color shows an orange suffusion.

Psychilis krugii (Bello) Sauleda Grows in the limestone formations in the South and Southwest of PR. Likes drier conditions (it even grows on cacti) and tolerates a lot of direct sunlight [button] and [button].

Psychilis monensis Sauleda Line Drawing Grows on Isla de Mona on the West Coast. Growing conditions like krugii. Smaller in size than krugii and it is green in color. There is one awarded by the AOS. [Psychilis monensis 'Ponce' CBR/AOS (Description and picture in AQ 25 p 12)

Since we are talking about the Psychilis of Puerto Rico, let's us take a break from the endemic species to view the 5th Psychilis species that is found in PR: Psychilis macconnelliae Sauleda

Let us not confuse the Psychilis macconnelliae that grows in the Eastern coast of Puerto Rico and in the Island of Vieques with Psychilis bifida nor with the color form that is known from St Croix and Florida that is often confused with Psychilis bifida. The Puerto Rican form of the species is smaller, opens more flowers simultaneously (check the line drawings under monensis) and are a pale pink in color, generally paler than the ones shown in this photo.

Tolumnia prionochilia (Kraenzlin) Braem

In Puerto Rico, Tolumnia prionochilia hails from the Eastern islands of Vieques and Culebra. This species tolerates a lot of direct sun and dry conditions. Its Flowers are crowded at the end of a very long inflorescence. Flowers are yellow.

Broughtonia dominguensis (Lindley) Rolfe
Before you all jump on me, let me quote from Ackerman.

Bletia patula Graham [button] and [button].
This is a highly variable species. Ranges from pure whites and splashes to pink. AOS has granted three awards to two clones from Puerto Rico: a CHM to the clone 'Martha Lankford' (AQ 25 p 12) and 'Leidy' (AQ 17 p 194). The 'Leidy' clone got its CHM upgraded to an AM one year later (AQ 18 p 182). The 'Leidy' clone is an alba form of the species.

CAMPYLOCENTRUMS: Key to the Campylocentrums found in Puerto Rico

Campylocentrum fasciola (Lindley) Cogniaux

Campylocentrum filiforme (Swartz) Cogniaux ex Kuntze, [button] and [button], which should not be confused with Harrisella prorecta (Reinchenbach f) Fawcett & Rendle.

Campylocentrum micranthum (Lindley) Maury [button] and [button].

Campylocentrum pygmaeum Cogniaux

Cochleanthes flabelliformis (Swartz) Shultzes & Garay

Cyrtopodium punctatum (Linnaeus) Lindley Partially rare now…due to grazing, road building, and furniture and guitar making #1, #2, #3, #4.

Dichaea hystricina Reichenbach F

Dichaea pendula (Aublet) Cogniaux

Domingoa haematochilla (Reichenbach f) Carabia From Isla de Mona also known as Domingoa hymenoides.

Encyclia (now Prostechea) cochleata (Linnaeus) Dressler [3 color forms] #1, #2, #3. This table that appeared in a recent issue of 'Orchids' magazine summarizes the differences between Prostechea and Encyclia

Encyclia pygmaea (Hooker) Dressler [A "giant" of a flower] [button], [button] and [button].

Epidendrum anceps Jaquin [button] and [button].

Epidendrum ciliare Linnaeus [button] and [button].

Epidendrum jamaicense Lindley [button] and [button].

Epidendrum misserimum Reichenbach f

Epidendrum nocturnum Jaquin And compare it to its relative Epidendrum carpophorum Barbosa Rodrígues

Epidendrum rigidum Jaquin [button], [button] and [button].

Epidendrum secundum Jacquin [button] and [button].

Epidendrum vicentinum Lindley [Syn: Epidendriopsis vicentina (Lindley) Garay & Dunst.

Erythrodes plantaginea (L) Fawcett & Rendle

Eulophia alta (Linnaeus) Fawcet & Rendle

Govenia utriculata (Swartz)Lindley (Picture of one of the species considered synonymous)

Habenaria distans Griesbach

Habenaria monorrhiza (Swartz) Reichenbach f.

Habenaria odontopetala Reichenbach f [button] and [button].

Habenaria repens Nuttall
(To give you an idea of the range of this species, this photo was taken of a plant that bloomed in Flynn, Texas)

Isochilus linearis (Jacquin) R.Brown [Flower]

Jacquinella globosa (Jacquin) Schletchter

Jacquinella teretifoilia (Jacquin) Britton & Wilson

Koellesnsteinia graminea (Lindley) Reichenbach f [button] and [button].

Maxillaria cocccinea (Jacquin) L.O. Williams and compare it to the other 2 Maxillarias native to PR: Maxillaria acutifolia Lindley and Maxillaria parviflora (Poeppig & Endlicher) Garay.

Mesademus polyanthus (Reichenbach f.) Schletchter

Nidema ottonis (Reichenbach f) Britton & Millspaugh

Oeceoclades maculata (Lindley) Lindley YES THEY ARE EVERYHERE! Please notice the synonym under which it was photographed

Pleurotharis aristata Hooker To give you an idea of scale, that plant fits inside a quarter with room to spare.

Pleurothallis ruscifolia (Jacquin) R. Brown

There are two Tetramicras in Puerto Rico [although only one is reported]:

Tetramicra canaliculata (Aublet) Urban [This is a copy of the award slide of Tetramicra canaliculata 'Alondra' AM/AOS] For many years the conventional wisdom in PR was that what we called T. elegans ('Alondra' got is award under that species name which was changed after OIC validated award) was canaliculata; that elegans was not native to PR. But it is. Jut 5 miles up the road where 'Alondra' was collected there is one large population of the many populations of Tetramicra elegans (Hamilton) Cogn. that are located in the west mountain zone of Puerto Rico. Notice www.orchidspecies.com has it labeled as canaliculata. I have sent specimens to OIC of T. elegans and got the confirmation that is T. elegans. Nevertheless, T. elegans has not been annotated yet as in PR.

Lets view our favorite: Tolumnia variegata (Swartz) Braem. Tolumnia variegata was the original type species for the genus Oncidium until its segregation for that genus. This species grows in the coffee trees of the central mountains of PR and is known as "angelitos" - little angels. Needs, cooler temperatures, low filtered light, high humidity and good air movement. It is a variable species [button] and [button]. And, it is often confused with: Tolumnia leiboldii and, Tolumnia sylvestris

The species is highly variable to the point that you can collect different color forms on the same tree branch. In an attempt to explain the differences in form between the Hispaniola forms and the PR form of the species, Ragan and Sauleda have proposed the existence of a new species for PR. (Article includes pictures) Ackerman and M. Galarza-Pérez (Patterns and maintenance of extraordinary variation in the Caribbean Orchid, Tolumnia (Oncidium) variegata). Sys. Bot. 16: 182-194. propose an alternative explanation: variation as a function of growth of different individuals due to the higher degree of fertile seed in nature.

Tolumnia variegata shares its habitat with species like:

-Comparettia falcata Poepig & Endlicer [button] and [button]

-Epidendrum boricuarum Hágaster Y Sánchez

-Ionopsis satyriodes (Swartz) Reinchenbach f

-Ionopis utricularoides (Swartz) Lindley

The species I mentioned before are closely tied to the cultivation of coffee in PR and are affected by folklore (Orchids are parasites that should be removed from plants), land distribution patterns and inheritance laws, plagues that affect coffee trees and plague control, methods of cultivation and the new "Café de Sol"

There are seven species of VANILLA found in Puerto Rico. Of those, two
escaped from cultivation from the old Vanilla farms that were located in the mountain town of Adjuntas:

Vanilla plainfolia Jackson ex Andrews [button] and [button] and Vanilla pompona Scheide
Escaped from cultivation is at least a hybrid made by Knudson as part of an attempt of the Government of Puerto Rico to save the Vanilla industry.

The Native Species are:

Vanilla poiteaei Reinchenbach f

Vanilla dilloniana Correl

Vanilla barbellata Reinchenbach f.

Vanilla claviculata (W Wright) Swartz Line drawing

Vanilla mexicana Miller

Zeuxine straeumatica (Linnaeus) Schletchter

-The End