This paper is a list of the species of vascular plants collected or observed in and about Bahía de San Quintín in the marine meadows, salt marshes, dunes, coastal flats, and lava and pumice of the volcanos. The lists is bases primarily on collections made by R.F. Thorne and associates from Rancho Santa Ana Botanic Garden on various trips in 1983 to 1987. Additional species are included from collections made by others, especially by Reid V. Moran, deposited at RSA, SD and DS. The Thorne et. al specimens are mostly deposited at RSA, SD, MEXU, and BCMEX. This list contain a 45 families with 224 species, 27 of those species belived to be introduced in the area.

The present survey of Bahia de San Quintin in Baja California fulfills two pimary purposes: a search for basic information on an unpolluted enclosure as near southern California as posible, and the initiation of comparative investigations. This report forms an introduction to a series of articles to be published on the geology, hidrography and benthic life of the bay, an includes those descriptive features not being treated elsewhere.

Between January to December, 1985, samples were collected in seven representative tomato farms (El Seco, El Dátil, El Milagro, Valladolid Oeste y Sureste, Los Canelos y Los Pinos) of Valle de San Quintín. Areas were located in a map (scale 1:100,000). Each ranch were visited month to month during a year. For each location five samples were taken for each diferent species, the samples were identified and herborized ( each mounted plant show roots, stem, leaf, flowers and seeds) then registed and deposited in the BCMEX herbarium in the Facultad de Ciencias-U.A.B.C. in Ensenada. This document report a total of 48 species in 16 families identified, all of them phanerogams or vascular plants. The greatest diverity of species occurred in the family Graminae (144 species) and compositae (7 species). The largest number of species was found in the farms El Seco, Los Canelos and Los Pinos. All the species found are introduced

This study describes a relativily pristine salt marsh and ecotones that could serve as a comparison for understanding disturbed West coast marshes. The salt marsh and terrestial transitional vegetation of Bahía de San Quintín is composed of a low numers of species with only a few dominants, and it is similar to southern California marshes. The vascular plants present in the salt marshes of Bahía de San Quintín were identified according to Munz (1959) ans Shreve and Wigging (1964) Voucher specimens are on file in the california State University, Los Angeles (CSULA) herbarium.

For this study seven littoral salt marshes and 14 upland transition zones were selected for a quantitative study. Each of the selected marshes was divided into three littoral or marsh zones and one transitional zone. Seven additional transition zones were sampled toinclude the variability of the upland vegetation. Each zone in each study marsh was sampled with 160 (25 X 25 cm² ) quadrants; percent plant cover was visually estimated for 16 quadrants in each zone. Transition zone were sampled differently, four representative line intercepts were taken on different slopes. Depth to soil moisture was taken in each transect of the transition zone. Depth to the salt marsh water table was obtained by boring soil cones at 1m intervals along 30m, each hole was dug to a maximun of two meters.

On the 17 saltmarsh species found in Bahía de San Quintín, five represent tropical floristic elements. The marsh flora is composed of only 17 phanerogams species. The transitional flora is representes by 33 species from 28 genera and 19 families. Of these species, 12 are characteristically found in salt marsh, and 21 are normallly associated with desert and coastal uplands.

Se realizó un estudio fitosociológico de la comunideades de plantas vasculares existentes en los saladares y manglares de la península de Baja California. La zona de estudio se extendio desde el estuario del Río Tijuana en el condado de San Diego, California, E.U.A. hasta el Llano de Magdalena en Baja California Sur, México. Se aplico la metodología fitosociológica sigmatística. En cada una de las localidades estudiadas se analizarón diversos parámetros: zonación, composición florística, medidas microtopográficas y análisis fitosociológico. Se reconocio un total de 16 asociaciones, de las cuales nueve de estas asociaciones se pueden encontrar en la Bahía de San Quintín. Para cada una de las cuales se comentan diversos aspectos dinámicos, estructurales, ecológicos, biogeográficos, florísticos y sintaxonómicos. Se discute la zonación existente en los saladares y manglares estudiados.

The objetive of this paper is to summarize, mainly through a review of the literature, beach vegetation and its phytogeography along the Pacific Coast of North America between Point Barrow, Alaska (approximately 71°N),and Cabo San Lucas, at the southern tip of Baja california (approximately 23°S). The survey of beach vegetation does not include species of adjacent habitats such as dunes, ocean-facing cliffs, saltmarshes, shingle beaches and the intertidal unless those species are also characteristic of beach vegetation. Most of the information summarized in this section comes from floras. Show in a table a list of 46 species with some subspecies, showing latitudinal ranges and distribution patterns for the characteristic beach species of the North American Pacific Coast.

One hundred and twenty plants species were collected on the dunes along the 1400 Km-long western coast of the peninsula of Baja California, México. At sixteen of the thirty-two sampled locations between Tijuana, B.C. and La Paz, B.C.S., transects were made at right angles to the shore to record cover and zonation of these species. Abronia maritima, was found along the entire coast and it was the major foredune-builder throughout most of its range. The ranges of most of the others species fall into one of the three groups corresponding to regions of inland vegetation and to Köppen climatic types of semi-arid (BS) south to 30°N, arid (BW) in the central part, and aris tropical (BSh) south of 30°N. Within each region the vegetation on dunes inmediately above the beach is more uniform than that on the backdunes, where the shrubby vegetation varies acording to the degree of surface stabilization.

Approximately 107 species of plants are endemic to Northwestern Baja california; many of these endemic and near-endemic species are dominant in this region; however a umber are considered rare on both sides of the border. The differences between coastal sage scrub and maritime succulent scrub communities from those of the Californian Floristic Province north of the border can be demostrated by discussing the vegetation and endemics of a number of important localities, proceeding from the border southward and from coast inland. This paper shows a list of 30 endemic species restricted to Northwestern Baja California.

Se proporciona información de las características fisiográficas e hidrológicas, históricas y socio-económicas, dando enfasis en las actividades acuícolas y pesqueras de Bahía San Quintín. Se hace un enfásis especial sobre las actividades acuaculturales que se han desarrollado en el Estado de Baja California en la última decada. La historia del programa de moluscos, los propósitos y objetivos. Se incluye un censo de la producción por especies en 1987. Se identifican y evaluan las fuentes contaminantes de la bahía, se efectuaron muestreos de agua superficial para análisis bacteriológicos, determinado con el método del número más probable. Los resultados de coliformes indicaron que para algunas estaciones los valores exceden de 70 NMP/100ml. En el análisis estadístico efectuado se observa que durante los dias de muestreo, el 10% del total de las muestras no execede el valor de 230 NMP/100ML. Sin embargo los aspectos hidrodinámicos del área de estudio ofrecen condiciones ventajosas para el recambio de agua, esto garantiza la eliminación de cualquier evento contaminante, en lapsos muy cortos de tiempo.

These are unpublished field notes of the authors that have been taken during several projects carried out in the wetlands of Baja California. They include information from 1988 to date and are mostly on birds and their habitats.

Este trabajo se realizó como una respuesta a la inquietud de los autores debido a la preocupación por la construcción de los desarrollos turísticos que se tienen planeados en el área de Bahía San Quintín. En el se habla de la importancia biológica del área (flora y fauna), así como del desarrollo y uso sustentable en Bahía San Quintín, importancia histórico cultural del área y mediante trabajo de campo se hizo un inventario de la flora y fauna. Se da una opinión técnica en donde se explica que Bahía San Quintín, reune condiciones ecológicas e históricas que la hacen única en todo México, en toda la región mediterranea y en el mundo.