The following summary of 8 endemic tree genera reduced 

 to 1 is revised from an earlier article (7). 



Four currently accepted genera with endemic tree 

 species were named from Puerto Rico and another from 

 both the Virgin Islands and Puerto Rico. However, a 

 second species discovered later on another island 

 eliminated 3 endemic genera. Two other segregate genera 

 have been reduced to synonymy, and another merits fur- 

 ther study. Only Montezuma is now limited to Puerto 

 Rico, though Stahlia is almost so. 



Montezuma Sesse & Moc. (1824; Malvaceae, mallow 

 family) is the best known of these 8 genera. It was named 

 for the Aztec ruler in Mexico and erroneously confused 

 with Mexican collections. This genus was designated in- 

 dependently as Maga Urban (1912), and a second species 

 from Cuba has since been placed in a separate genus. The 

 only species, 151, Montezuma speciosissima Sesse & 

 Moc, maga, with very large red flowers, is native in the 

 moist limestone forest region of Puerto Rico. It has been 

 planted extensively for ornament and shade in other parts 

 of the island and has been introduced through the West 

 Indies to southern Florida. Closely related to the genus 

 Thespesia and named simultaneously T. grandiflora DC. 



Stahlia Bello (1881; Leguminosae, legume family) has 

 a single species, 79, Stahlia monosperma (Tul.) Urban, 

 cobana negra, first distinguished in 1844. It is a small or 

 medium-sized tree rare in coastal forests of southwestern 

 and southeastern Puerto Rico and in Vieques. After- 

 wards found near Macao, eastern Dominican Republic, it 

 technically is no longer endemic. 



Pleodendron v. Tieghem (1899; Canellaceae, canella 

 family) was based on 522, Pleodendron macranthum 

 (Baill.) v. Tieghm., chupacallos, first named in 1882. 

 Small or medium-sized tree, very rare in forests in lower 

 Luquillo Mountains and moist limestone regions. A sec- 

 ond species, P. ekmanii Urban (1928), was added from 

 Haiti. Incidentally, this genus has been in Puerto Rico a 

 long time, according to Graham and Jarzen (4). They 

 reported finding pollen of Oligocene age. 



Goetzea Wydler (1830; Solanaceae, nightshade family) 

 is represented by 694, Goetzea elegans Wydler, 

 matabuey. Small tree, very rare and local, known only 

 from a few places in the moist limestone and moist 

 coastal forests. Worthy of cultivation for its showy 

 orange flowers and orange fruit. A second species, G. 

 ekmanii O. E. Schulz (1933), was named from the 

 Dominican Republic and Haiti. Airy Shaw (30) estab- 

 lished the distinct family Goetzeaceae for a small relic 

 group of uncertain affinities with 5 genera and 7 species 

 in Mexico and the West Indies. This Puerto Rican species 

 may be the easternmost. 



Sabinea DC. (1825; Leguminosae, legume family) was 

 based on 389, 5. florida (Vahl) DC, retama, wattapania, 

 named from St. Thomas in 1793. Shrub or small tree 



locally common in northern Puerto Rico, Culebra, Vie- 

 ques, and Virgin Islands. Sparingly planted as an or- 

 namental for the masses of bluish purple flowers. This 

 genus now has 2 more species, a shrub endemic to central 

 and western Puerto Rico, S. punicea Urban, and another 

 shrub in Dominica. 



Menendezia Britton (1925; Melastomataceae, 

 melastome family) was set up from the genus Tetrazygia 

 Rich, for 3 endemic tree species of Puerto Rican moun- 

 tains. This segregate was not accepted in the second 

 volume. 



Fishlockia Britton & Rose (1928; Leguminosae, legume 

 family) was created for a single species endemic to 

 Anegada, Acacia anegadensis Britton (1916). This 

 segregate was not accepted afterwards. 



Cybianthopsis (Mez) Lundell (Wrightia 4: 68. 1968; 

 Myrsinaceae, myrsine family) was elevated from a 

 subgenus distinguished in 1901 for 1 endemic tree species 

 of Luquillo Mountains, Grammadenia sintenisii (Urban) 

 Mez or Cybianthopsis sintenisii (Urban) Lundell. Further 

 study seems desirable before acceptance of this segregate. 



Trees Absent From Puerto Rico 



Certain families and genera of trees widespread on the 

 continent are absent from Puerto Rico and the Virgin 

 Islands, or poorly represented there, as noted previously 

 (7). Apparently these groups have not been successful in 

 crossing the ocean barriers, though some may have 

 become extinct after arrival. Accordingly, Puerto Rico, 

 like oceanic islands in general, has a relatively poorer 

 flora than corresponding continental areas. Islands, 

 however, compensate by having greater numbers of 

 endemics. 



Puerto Rico has 85 plant families with native tree 

 species. In comparison, Costa Rica in Central America 

 has about 106 and Venezuela in northern South America 

 has about 100. Mexico has a high number, about 106, 

 because several north temperate families are present. 



Most of the missing plant families have relatively few 

 species and perhaps less chance of reaching the island. 

 Among those without native tree species in Puerto Rico 

 are Humiriaceae, Lecythidaceae, Monimiaceae, Myristi- 

 caceae, Proteaceae, and Vochysiaceae. The family 

 Tiliaceae has no native tree species but is represented by 2 

 genera of shrubs and herbs. There are only 3 native 

 species of Bombacaceae. 



Puerto Rico's only native conifer, Podocarpus cor- 

 iaceus (Podocarpaceae), is of South American origin. 

 Northern conifers are absent. The genera Pinus 

 (Pinaceae) and Juniperus (Cupressaceae) are native in 

 continental United States, Bahamas, Cuba, and Hispani- 

 ola but not as far as Puerto Rico. 



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