Manual de Plantas de Costa Rica 203 
Trees—Inga (54), Ocotea (45) 
Shrubs— Piper (80), Psychotria (75) 
Vines—Passiflora (47), Ipomoea (40) 
Herbs—Thelypteris (85), Cyperus (58) 
Epiphytes—Epidendrum (158), Pleurothallis (152) 
An observation from the graphics in Fig. 3 is that species diversity is spread some- 
what more equitably among vines, trees, and shrubs than among epiphytes and herbs. 
Relatively few large families account for much of the diversity in the latter two groups, 
whereas many families contribute significantly to the diversity of the former three habit 
types. This is particularly true for epiphytes, where all of the top five families special- 
ize, in a sense, on the epiphytic mode (see also Burger, 1985; Gentry & Dodson, 1987). 
(Fig. 3 is to be interpreted according to the following example, from “Epifitas”: 1115 
species of Orchidaceae are epiphytes, representing 53% of total epiphyte species [“*% de 
todas las spp. de epifitas ...”], and 86% of Orchidaceae species are epiphytes [“% de 
las spp. de la familia... ”].) 
One of the major structural differences between wet forests and the vegetation of 
drier, more seasonal (temperate) areas is not only greater species diversity, but, partic- 
ularly, greater diversity and abundance of epiphytes (see Gentry & Dodson, 1987). Epi- 
phytes make up 22% of the total vascular flora of Costa Rica. Over half of the species 
of epiphytes are orchids, while ferns and their allies account for a large portion of the 
remaining species. Together, vines and epiphytes, growth forms rare in climates more 
severe than that of Costa Rica (Burger, 1985), make up nearly 40% of the Costa Rican 
flora. Although terrestrial herbs account for the largest percentage of species (27%), 
that figure may be somewhat inflated, again due to the large number of once-reported, 
exotic grasses. Generally speaking, herbaceous plants do not form a very conspicuous 
part of the forest understory, except for large-leaved monocots (especially in forest 
edges and clearings). Nevertheless, as forests are cleared, trees, shrubs, and epiphytes 
give way immediately to herbaceous plants, so that it would not be surprising to learn 
that a complete analysis of the flora in Standley’s time, were it available, would reveal 
fewer species of herbs than now (assuming no change in the amount of natural savanna 
and paramo, habitats where herbs abound). 
Before embarking upon an analysis of the flora with respect to elevation, we should 
point out that the above statistics and those of the summary tables of the known flora 
are quite accurate estimates based on all the information available, including both Man- 
ual manuscripts and various databases. However, the following discussion relies almost 
exclusively on the INBio database (ATTA), in which distributional data are quite accu- 
rate and specimen records can be counted, but not all of the known species are repre- 
sented. For that reason, discrepancies in total species counts with those just previously 
mentioned will result. The totals mentioned in the text are from queries made of ATTA 
in November 2003, whereas the graphs were produced in April 2001. 
Standley’s (1937b) discussion of the Pacific tierra caliente is remarkable for being 
