M Claudio Delgadillo

The Neotropical-African Moss Disjunction

The neotropical flora shares with Africa about 334 specific and infraspecific moss taxa. Their disjunct range may be explained by an ancient land connection or by long-distance dispersal. Certain species may represent lineages whose taxonomic identity has been preserved for millions of years, but in species with rapid evolutionary rates the long-distance dispersal hypothesis is favored. An alternate explanation for the neotropics proposes secondary centers of dispersalfrom an ancestral continuous distribution in western Gondwanaland. Other hypotheses are inadequate because they concern themselves with few species or with portions of the general range.

The Mosses of the Tehuacán Valley, Mexico, and Notes on Their Distribution@@@The Mosses of the Tehuacan Valley, Mexico, and Notes on Their Distribution

There are 57 species and varieties in the known moss flora of the Tehuacan Valley; one of them, Phascum brittoniae, is new to the country. Their distribution in Mexico north of the 19-20ON line does not lend support to the hypothesis that the Neovolcanic Belt has served as a barrier to moss migration between southern and northern valleys. The Tehuacin Valley is a dry area in the south- eastern comer of the State of Puebla. According to Smith (1965a), the northern limit of the valley is about the Mexico City-Veracruz highway; it ex- tends westward to Sierra de Zapotitlin, south to the border with Oaxaca and eastward to the Sierra Madre Oriental or Sierra de Zongolica. The valley has been important from various points of view. It was selected as a critical area in the study of the establishment and diversification of maize (Smith 1965a); it is significant in understanding ages and patterns of domestication of Phaseolus spp. (Kaplan 1965), cucurbits (Whitaker & Cutler 1965) and selection and distribution of avocados (Smith 1966, 1969). Floristically, the Tehuacin Valley has been stud- ied by several authors, notably Bravo (1930), Mi- randa (1948) and Smith (1965b). The last author has also discussed floristic relationships. Recently,

Phytogeography of High-Elevation Mosses from Chiapas, Mexico

The highlands of Chiapas, Mexico, harbor temperate moss taxa which are common at similar or higher elevations in central and southern Mexico. The tropical taxa are confined, for the most part, to lowland moist sites, but in Chiapas several of them reach elevations beyond 2,700 m. This moss flora includes 155 taxa which may be divided into five phytogeographical elements; the most important in terms of number of species are the Meso-American and the Wide distribution elements. Aptychella and Grimmia are new to Chiapas and Daltonia lindigiana Hampe, D. te- nuifolia Mitt., and Orthotrichum trachymitrium Mitt. are new to Mexico.

Mosses of the Yucatan Peninsula, Mexico. III Phytogeography

There are 69 species and varieties of mosses reported for the Mexican part of the Yucatan Peninsula. These can be grouped into five floristic elements; the Caribbean element with 46 species indicates a close relationship of the peninsular flora with that of the West Indies. The endemic element is virtually absent. In Mexico the distribution of the peninsular flora includes the eastern and western coastal areas, ranging up to the Neovolcanic Belt in the center. This is similar to the distribution of characteristic area climates and vascular plant vegetation. There is no pen- insular effect evident in this area perhaps because of continued floristic exchange with mainland Mexico and the West Indies. The small size of the flora may be the result of intense human activity correlated with an undulating topography, absence of surface waterways, rapid drainage of rainfall and reduced number of microhabitats. Field work in the Mexican states of Campeche, Yucatan and Quintana Roo over a period of years has resulted in a collection of about 600 specimens. These have been studied to determine number of species and moss distribution in the Yucatan Pen- insula. The list of species was given in two preceding publications (Delgadillo, Cairdenas & Sharp 1982; Delgadillo & Cardenas 1982) and included 69 species and varieties. However, the information derived from this research requires further analysis to clarify the significance of moss distribution in the Yucatan Peninsula and update an earlier analysis (Steere 1935).

Flora Briofítica Ibérica. [Fascicle 1] Pottiaceae: Weissia, Astomum, Trichostomum

J. GUERRA AND R. M. CROS (Coordinators). Flora Briofı́tica Ibérica. [Fascicle 1] Pottiaceae: Weissia, Astomum, Trichostomum. 24 pages. 2002. [MU1999-2002.] [Fascicle 3] Pottiaceae: Syntrichia. 31 pages. [MU-2240-2002.] Sociedad Española de Briologı́a. Murcia. 2002. Price €10 each (soft cover). Available from: Patxi Heras, Museo de Ciencias Naturales de Álava, C/Fra. de las Siervas de Jesús 24, 01001 Vitoria (España). e-mail: bazzania@arrakis.es

Observations on Moss Succession on Paricutín Volcano, Mexico@@@Observations on Moss Succession on Paricutin Volcano, Mexico

Thirteen moss species were found on lava flows on Paricutin Volcano and 34 in the surrounding forest near Angahudn. The latter is within the area of partial destruction by cinder. Through fifty years ofprimary succession, the number of moss species has not increased substantially, but they seem to occupy all major microhabitats on the lava flows; mosses observed on soil in the forested area had ample opportunity for reoccupation, while the epiphytic taxa may have survived in protected microhabitats.

Lorentziella imbricata and Oreoweisia delgadilloi in Mexico

Lorentziella imbricata (Mitt.) Broth., currently known from the United States (Texas) and South America, is reportedfrom Mexico for thefirst time. The known distribution of Oreoweisia delgadilloi Robins. & Bowers is extended to central Mexico.

Astomiopsis x altivallis (Musci: Ditrichaceae), a Putative Interspecific Hybrid in Mexico

Astomiopsis amblyocalyx C.M. and A. exserta (Bartr.) Snider are sympatric in the highlands of central Mexico where they are apparently able to interbreed, resulting in putative hybrid sporophytes-on A. amblyocalyx gametophytes--which are morphologically intermediate between those of the presumed parental species. The stomata and spores are, however, smaller in the putative hybrid sporophytes.

Morinia saitoana, A New Species of Pottiaceae (Bryopsida) from Mexico

Morinia saitoana is described as a new species from material col- lected in Cofre de Perote, Veracruz, Mexico. With this addition, the genus consists of three species and two varieties, distributed from Mexico to northern South America. Specimens of a moss recently collected at high elevations on Cofre de Perote in Ve- racruz, Mexico, are here recognized as representing a new species in the Latin American genus Morinia Card. (Pottiaceae). The following combination of character states is diag- nostic: leaves sharply recurved to squarrose above a sheathing base; lower leaves red- brown; margins of the upper leaf narrowly recurved and bistratose; upper laminal papillae low, crowded, multiplex, 2-4 per cell surface, costa with hydroid (Begleiter) cells, peri- chaetial leaves enlarged and sheathing the seta, capsules long-cylindric and peristome teeth filamentous, long, orange and twisted. The new species, which we name for Dr. Kamezo Saito in recognition of his fine studies on the Pottiaceae of eastern Asia, is distinguished from other taxa of the genus (see Zander 1978) by the key given below.