TREE SPECIES, DESCRIPTIONS AND ILLUSTRATIONS 



TREE-FERN FAMILY (CYATHEACEAE) 

 1. Helecho gigante, tree-fern Cyathea arborea (L.) J. E. Smith 



Tree-ferns, among the most beautiful plants of 

 tropical mountains, are common in Puerto Rico. 

 Tiiey are readily recognized as ferns by their lace- 

 like fern leaves unrolling from a coil at the apex 

 and by the absence of tlowers, fruits, and seeds, 

 while their slender unbranched trunks, leafy only 

 at the summit, qualify them as trees. 



This species, the commonest of 5 or 6 kinds of 

 trunked ferns reaching tree size in Puerto Rico, 

 is characterized by: (1) slender unbranched 

 brown trunk, scaly but spineless, usually with 

 large oval leaf scars in the upper part and bearing 

 at apex a crown of about 10-18 large spreading 

 leaves; (2) feathery (.3-pinnate) leaves mostly 

 6-10 feet long, the thin blade clivided 3 times, 

 ending in a long pointed tip curved downward; 

 and (3) small brown ball-like masses less than 

 i/ie inch in diameter, borne on the underside of 

 some leaves and producing numerous powdery 

 spores. 



A vei-y handsome small evergreen tree to 30 feet 

 or more in height, with trunk 3-5 inches in diame- 

 ter and stately crown of graceful leaves, ovate in 

 general outline. This species is spineless through- 

 out, though certain kinds have spiny trunks and 

 leaf axes. There is no conspicuous bud, but usu- 

 ally 1-4 young unrolling leaves, actually alternate 

 though crowded. 



A mature leaf has a light brown axis scaly at 

 base and many yellow-green secondary axes as 

 much as 2 feet long, each bearing feathery taper- 

 ing branches less than 6 inches long. The" numer- 

 ous regularly arranged leaf segments are narrowly 

 oblong, % inch or less in length, rounded at apex, 

 and with the minutely wavy-toothed edges turned 

 under. The thin segments are yellow green on 

 both sides. A dead leaf soon falls, leaving a large 

 oval scar. 



Some older leaves bear minute brown balls or 

 beads (sori) in 2 rows on under surface of seg- 

 ments, composed of numerous spore cases (spor- 

 angia) which shed powdery masses of microscopic 

 spores. Under favorable conditions spores, like 

 seeds, develop into new plants. 



Trunks of giant ferns differ from those of most 

 trees in several ways. The smoothish surface is 

 brown and scaly, often covered below with masses 

 of smaller plants, such as mosses, liverworts, and 

 ferns, and with many small black roots projecting 

 from the enlarged base. Not divided into bark 



and wood, the trunk does not grow in diameter. 

 There is a hard black outer layer Vs i"ch or more 

 in thickness and a central white soft pith contain- 

 ing a ring of brown bundles which serve for con- 

 duction and strength. 



Though not solid wood, the hard trunks are dur- 

 able and resistant to decay and termites. Else- 

 where, trunks of tree-ferns have served as posts, 

 frameworks of houses, supports for vanilla plants 

 and other orchids, and as water bars for drainage 

 along mountain trails. The Carib Indians used 

 the stems to preserve and carry fire, which can be 

 maintained for hours without smoke or flames. 



These luxuriant ferns seem to thrive following 

 opening of the areas and construction of mountam 

 roads, often growing abundantly along the cut 

 roadside banks. One of the most easily accessible 

 areas for viewing these odd plants is along the 

 highway crossing the Luquillo Mountains. 

 Though very ornamental in their native moun- 

 tains, tree-ferns seldom are cultivated in Puerto 

 Rico. It is reported that small plants can be. trans- 

 planted successfully and garden-grown in moist 

 regions, even at sea level. 



In lower and upper mountain forests of Puerto 

 Rico growing as a small understory tree and es- 

 pecially common in open areas such as ravines, 

 lianks, and roadsides. Also recorded from St. 

 Thomas and Tortola, now probably rare on the 

 latter and not observed there in 1954. 



PuiiLTC FORESTS. — Carite, Guilarte, Luquillo, 

 Maricao, Toro Negro. 



Range. — Greater Antilles, St. Thomas, Tortola, 

 and Lesser Antilles in Saba, St. Kitts, Nevis, 

 Guadeloupe, Dominica, Montserrat, Martinique, 

 St. Lucia, St. Vincent, and Grenada. Also in Trin- 

 idad. Recorded as rare in lowlands of eastern 

 Mexico. 



Other common names. — helecho arboreo, hel- 

 echo, palmilla, camaron, camaroncillo (Puerto 

 Rico) ; camaron, helecho arlx)l, palmera sin espinas 

 (Cuba) ; tree-fern (English). 



Several species of trunked fenis of this and re- 

 lated genera (HemifeUa and Alf<ophila) are native 

 in mountain forests of Puerto Rico though uncom- 

 mon to rare and usually not reaching tree size. A 

 related large tree-feni with small spines on the 

 trunk is Cyathea hritfoniana Maxon. Another 

 large tree-fern with leaves only twice pinnate (2- 

 pinnate) and with spines is C. pubescens Mett. 



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