S. Rob Gradstein

An altitudinal zonation of tropical rain forests using byrophytes

Recent studies on the cover, phytomass and turnover of bryophytes in tropical rain forests along altitudinal transects in the high mountains of Columbia, Peru, Borneo and Papua New Guinea reveal the existence of similar altitudinal zonations in different parts of the humid Tropics. As bryophytes are excellent climate indicators, are rather few in terms of species number, have very wide geographical ranges, and are a characteristic component of the structure of the tropical rain forest, they may be useful tools for the construction of a general scheme of the altitudinal zonation of tropical rain forests. Five altitudinal belts are distinguished: the lowland forest, the submontane forest, the upper lower montane forest, the montane forest, and the subalpine forest. A comparison is made with other zonation terminologies and the elevational variations of the belts, due to local climate, latitude, and other factors, are discussed briefly.

Species richness and habitat diversification of bryophytes in submontane rain forest and fallows of Bolivia

An analysis of corticolous bryophyte diversity on whole trees in primary rain forest and 4-15-y-old fallows at 500-650 m in the Alto Beni, Bolivia, showed a significantly decreased diversity of bryophyte families and moss species in the fallows. However, liverwort diversity was scarcely lower in the fallows, except in the very young (4 y old) ones. Fallows had a significantly higher percentage of smooth mat species (72%), which may reflect the warmer, drier microclimate in the fallows. About half of the bryophyte species of the rain forest had re-established in the 10- 15-y-old fallows. The majority of these are ecological generalists and sun epiphytes; a small minority are shade epi- phytes. Re-establishment of ecological specialists is slower than that of generalists. Species richness in the primary forest is highest in the canopy; in the fallows it is highest in the understorey due to striking shifts of species and specialized growth types (rough mats, fans, tails) towards lower heights on the trees in the fallows. These shifts corre- spond well with measured changes in air temperature and air humidity in the fallows as compared with the forest.

Bryophyte Diversity of Ficus Tree Crowns from Cloud Forest and Pasture in Costa Rica

A total of 127 bryophyte species (50 mosses, 76 liverworts, and 1 hornwort) was encountered in the inner crowns of six Ficus tuerckheimmi trees in a lower montane wet forest landscape: 109 on three intact forest trees and 76 on three isolated trees. Fifty-two species were found only on the intact forest trees, while only 18 species were exclusive to the isolated trees. Bryophyte species richness, bryophyte cover, and the frequency of pendents, tall turfs, tails, and fans were significantly higher in intact forest trees. Inner crowns of isolated trees had higher rates of evaporation, had higher macrolichen cover, and were more exposed to sunlight than inner crowns of intact forest trees. Ordination analysis revealed one dominant pattern in bryophyte composition in the inner canopy: a desiccation gradient ranging from sheltered sites in the intact forest trees to exposed sites in the isolated trees.

A key to the Hepaticae and Anthocerotae of Puerto Rico and the Virgin Islands

A key emphasizing vegetative characters is provided to 237 species in 92 genera of liverworts and hornworts recorded from Puerto Rico and the Virgin Islands. Poorly known taxa and doubtful records have usually been omitted from the key and are referred to in notes. A clas- sification and a list of synonyms are provided. The following new names and new combinations are proposed: Anomoclada portoricensis (Hampe & Gott.) Vdira, comb. nov., Macrolejeunea cerina (Lehm. & Lindenb.) Gradst., comb. nov., and Neurolejeunea sastreana Gradst., sp. nov.

Plagiochila rutilans (Hepaticae): A Poorly Known Species from Tropical America

Abstract The neotropical liverwort, Plagiochila rutilans Lindenb., is conspecific with P. remotifolia Hampe & Gottsche, P. farlowii Steph., P. harrisana Steph, and P. organensis Herzog. Plagiochila standleyi Carl is reduced to a variety of P. rutilans. Plagiochila gymnocalycina (Lehm. & Lindenb.) Mont. and P. portoricensis Hampe & Gottsche (= P. simplex (Sw.) Lindenb.) are excluded from the synonymy of P. rutilans. Plagiochila rutilans var. liebmanniana Gottsche is a synonym of P. crispabilis Lindenb.; P. rutilans var. laxa Lindenb. and var. angustifolia Herzog are conspecific with P. gymnocalycina. Sporophytes of P. rutilans are described for the first time. Fresh material of P. rutilans exhibits a distinct odor of peppermint caused by the presence of several menthane monoterpenoids, principally pulegone. NMR (nuclear magnetic resonance) fingerprints and GC-MS data indicate that the lipophilic secondary metabolite profiles are distinct for the two varieties accepted in this study.

Additions to the hepatic flora of Costa Rica III

35 species of hepatics are newly reported from Costa Rica, including 15 which were previously unknown to Central America. Notes on the geographical distribution and habitats of the species are provided.

On the Ecology and Conservation of Spruceanthus theobromae (Lejeuneaceae, Hepaticae) from Western Ecuador

Abstract The liverwort Spruceanthus theobromae (Spruce) Gradst., known from a single extant site and considered a critically endangered species, was detected on trunk bases of Theobroma cacao in 12 cacao plantations with low management intensity in western Ecuador. Its host specificity and exclusive occurrence in plantations are unique ecological features of the species. According to the IUCN criteria, Spruceanthus theobromae qualifies as a near threatened species (LR/nt) and should be removed from the World Red List of Bryophytes. The continued existence of cacao plantations with low management intensity in western Ecuador is of great importance to the conservation of local bryophyte diversity and is crucial to the survival of Spruceanthus theobromae.

The Genera Thysananthus, Dendrolejeunea, and Fulfordianthus gen. nov. (Studies on Lejeuneaceae Subfamily Ptychanthoideae XXI)

The genus Thysananthus (Lejeuneaceae subfam. Ptychanthoideae) has about 10 species in two subgenera and occurs in rain forests throughout the tropics. The center of diversity is in Southeast Asia. Dendrolejeunea and Fulfordianthus are segregatedfrom Thysananthus on the basis of their dendroid growth habit, regularly pinnate branching, and differentiated cortex. Lack of trigones and oil bodies, and pycnolejeuneoid innovations, are the unique features of Fulfordianthus. A key is provided to the genera, subgenera, and species of this complex. Dendrolejeunea is monotypic andAsiatic in distribution whereas Fulfordianthus contains two species endemic to CentralAmerica and the Choc6 region of northwestern South America. These two genera are elements of the shaded understory ofold-growth tropical rain forest and their continued existence is threatened by destruction

New Moss Records for Mexico from the Lacandona Tropical Rain Forest, Chiapas

Abstract This paper reports nine new moss records for Mexico from the Lacandona Forest: Calymperes rubiginosum, Fissidens guianensis var. guianensis, Mniomalia viridis, Orthostichella hexasticha, Orthostichopsis praetermisa, Phyllodrepanium falcifolium, Syrrhopodon flexifolius, Syrrhopodon africanus subsp. graminicola, and Syrrhopodon hornschuchii. Findings reported here demonstrate that there is still incomplete knowledge of the moss diversity in the Lacandona tropical rain forest region. Future research in tropical forests of southeastern Mexico and Central America will help to corroborate the continuity of distributional patterns from South America to North America through the Central American bridge.

On the blue stem colour in Plagiochila longispina Lindenb. & Gottsche (Plagiochilaceae)

Abstract The blue colour of the shoot tips of Plagiochila (sect. Glaucescentes ) longispina is caused by the presence of blue oil bodies in the outer cell layers of the stem. Oil bodies disintegrate in microscopical preparations after a few minutes and blue-coloured drops accumulate under the cover glass. It is suggested that the substances of these drops become associated with cortex cell walls during drying of plant material, leading to the blue colour of these walls in herbarium specimens.