NATURAL HISTORY OF COSTA RICA RIDGWAY. 311 



greater part of its extent, palms are very little in evidence ; often none 

 at all can be seen in an extensive expanse of tree tops. Once inside, 

 however, and where the trunks of the trees are exposed by clearings, 

 the difference is so great that even the most luxuriant broad-leaved 

 forests of the more southern United States convey but a faint sug- 

 gestion of their bewildering exuberance and infinite variety in de- 

 tails of their composition. 



The average tropical forest is practically impenetrable, often ab- 

 solutely so without free use of the wood knife or machete. The 

 trees, as a rule, are no closer together, and the biggest rarely larger 

 than in the heaviest of our virgin hardwood forests. The occasional 

 "giants" excel ours mainly in the great development of buttresses 

 at the base, and wider expanse of their crowns ; and I have never seen 

 in tropical forests single tree trunks surpassing in uniform thickness, 

 length, or symmetry some of the gigantic sycamores, tulip trees, 

 black walnuts, pecans, burr oaks, and bottom red oaks which form- 

 erly grew in the rich alluvial bottom lands of our Middle West. But 

 in tropical forests there are no open spaces or vistas; almost every- 

 where between the larger trees is a tangled maze of lesser vegetation 

 through which a path must be cut as one proceeds. It is this minor 

 growth that displays almost endless variety in form, size and color 

 of foliage, for the leaves of the trees themselves are singularly uni- 

 form in type. Cablelike vines are stretched from tree to tree and 

 hang in loops or spirals, some of them zigzag and curiously flattened ; 

 aerial roots of epiphytic plants growing on the larger branches of the 

 trees are suspended from tree tops, hanging straight down like cords 

 or ropes, frayed or fringed at the lower end by incipient rootlets, or, 

 having reached the ground, have taken root there and will soon form 

 separate tree trunks, or have already done so; climbing plants of 

 numberless kinds ascend these cablelike growths, and a network of 

 climbing ferns and other tough-stemmed climbing plants interlace 

 the whole. Each tree is itself a veritable botanical garden, for not 

 only are the lofty crowns burdened with masses of parasitic or epi- 

 phytic plants — ferns, orchids, bromeliads, aroids, cacti, and others 

 belonging to unfamiliar orders — but the trunks themselves are simi- 

 liarly decorated. Often what seems at first sight to be a single trunk 

 will on closer view prove to be a compound one, the original stem 

 lost in a confusion of several twisted woody climbers, the foliage of 

 each forming a separate mass or tier. The ground itself is covered 

 with plants of numerous kinds, lycopodiums, peperomias, ferns, etc., 

 the kinds varying greatly with locality. None of our northern for- 

 ests contain anything like so great a variety in the trees themselves ; 

 rarely are two examples of the same species seen near together, but 

 usually each tree is different from all others in its vicinity. 



