Figure 3.11. Mucuna urens seed pods with
urticating hairs. Photograph by Barbara L
Clauson.rather derive all of their moisture and nutrients from
the atmosphere, from materials dissolved in mist and
rain water flowing down the supporting stems, and
from intercepted organic litter accumulated around
their roots. The term pertains here to plants whose
seeds germinate on other plants (including parasites
such as the Loranthaceae). Many normally epiphytic
species (especially ferns) can also be found occasion-
ally growing on rocks, fallen logs, or moss mats on
soil. In the cloud forest, terrestrial plants, such as
palms, occasionally grow as epiphytes, but this is an
exception to their normal ground-based growth pat-
tern (but see Putz, "Trees on Trees," p. 70).
Hemiepiphytes ("half epiphytes") begin life as epi-
phytes; as they grow, they send roots to the ground
where they gain access to additional nutrients and
water from the soil. Hemiepiphytes may drop long
aerial roots directly to the ground (Ficus, Clusia [Fig.
3.13]) or send their roots down the trunk of the host
tree (Blakea, Cavendishia, Clusia, Ficus, Marked).
Lianas are distinct from hemiepiphytes in sending up
climbing stems from seeds that germinated in the soil
(Marcgravia), but their functional growth forms can be
similar. Many species of Araceae and Cyclanthaceae
begin life as tree trunk climbers, but their lower stems
do not increase in diameter and may eventually die
back, stranding them as apparent epiphytes. Whether
a plant grows as a liana or an epiphyte depends on seed
germination requirements; seeds of some fig species do
not germinate in ground soil, but only in the arboreal
soil that accumulates in the crotches of host trees (Titus
et al. 1990; see Titus, "Why Strangler Figs," p. 71).
Epiphytes are the most species-rich life form in the
Monteverde flora, with 878 species, including 230
dicot species in 25 families, 471 monocot species in
5 families, and 177 ferns and their relatives in 13 fami-
lies (see Ingram, "Epiphytes, p. 72 and Appendix 2).
Orchidaceae is the richest epiphyte family in the
Monteverde region, with more than 450 species of
epiphytes (see Atwood, "Orchids," p. 74 and Appen-
dix 3), followed by Araceae, Bromeliaceae, Gesneri-
aceae, and Piperaceae, each with more than 30 spe-55 Plants and Vegetation