Manual de Plantas de Costa Rica 105 
rhombea, Sida linifolia, Sloanea terniflora, Trigonia rugosa, Waltheria glomerata, and 
Ximenia americana. However, we also find here elements of the northern moist forests, 
such as Aegiphila cephalophora, Bourreria oxyphylla, Cnestidium rufescens, Cyno- 
metra retusa, Dialium guianense, Pithecellobium furcatum, Schefflera morototoni, 
Senna undulata, Trigonia laevis, Xylophragma sp. nov., and Xylopia frutescens. Pithe- 
cellobium furcatum and Xylophragma sp. nov. are known only from here in Costa Rica. 
Of course, in addition to these lowland elements, species common in the main massif 
of the Cordillera de Guanacaste also occur on Cerro El Hacha, such as Diospyros di- 
gyna, Myrsine pellucidopunctata, Pilocarpus racemosus, Polygala costaricensis, and 
Rhipidocladum racemiflorum. 
In the elevational band of approximately 600—1500 m, some noticeable effects of 
seasonality on forest structure and composi- 
tion are dense, compact tree crowns (as a re- 
sult of wind action) and a relatively open and 
clean understory. The canopy and middle 
levels are characterized by an abundance of 
such species as Allenanthus erythrocarpus, 
Billia hippocastanum, Daphnopsis ameri- 
cana, Erblichia odorata, Ficus tuerckheimii, 
Licania riverae, Manilkara chicle, Myrcian- 
thes montana, Panopsis costaricensis, Par- 
mentiera valerioi, Picrasma excelsa, Pouteria 
exfoliata, P. glomerata, Quercus oleoides, 
Sarcaulus brasiliensis, Symplococarpon pur- 
pusii, Styrax argenteus, and Tapirira mexi- 
cana. The understory and intermediate levels 
are quite rich in species of Psychotria 
and Myrtaceae, but species such as Acido- 
ton nicaraguensis, Actinostemon caribaeus, 
Amyris balsamifera, Angostura granulosa, 
Euphorbia elata, Laetia thamnia, Pelto- 
stigma guatemalense, Pilocarpus racemo- 
sus, Rhipidocladum pittieri, and R. racemiflorum are also common. A few species of this 
region are also shared with the plateau of Santa Rosa National Park, to as low as 250— 
300 m, e.g., Actinostemon caribaeus, Casearia praecox, Erblichia odorata, Hybanthus 
yucatanensis, Krugiodendron ferreum, Styrax argenteus, and Zanthoxylum fagara. 
Toward the summits of this cordillera, especially above 1500 m where the climate 
is wetter, characteristically montane elements begin to appear, although some of these 
are shared with the lower elevational band just mentioned. Some species typical of this 
zone are Beilschmiedia alloiophylla, B. brenesii, Bourreria costaricensis, Casearia 
Panopsis costaricensis, Volcan Orosi 
near Estaci6n Maritza (2000) 
tacanensis, Cavendishia capitulata, Ceiba rosea, Centropogon costaricae, Chiococca 
