Abstract The spore wall of Riccia plano-biconvexa, R. fruchartii, R. cavernosa, R. stenophylla, and R. curtisii was analyzed using light microscopy. The study involved cytochemical analysis to distinguish the different layers of the sporoderm and assess their chemical composition. In all the species studied, the sporoderm was found to have a tri-layered exine, consisting of a lamellar exine 1 that forms ridges and depressions, an intermediate exine 2, and a thick and generally discontinuous exine 3. Cytochemical studies indicated that exine 1 and 2 are composed of sporopollenin, while exine 3 is a mixture of sporopollenin and polysaccharides. The intine, on the other hand, is the only layer that is purely cellulosic and contains pectins. Based on the chemical composition and structural organization, exine 1 and 2 can be categorized as ectexine while exine 3 corresponds to an endexine. We emphasize the importance of using cytochemical tests to study the spore wall in liverworts and other bryophytes. planobiconvexa, planobiconvexa plano biconvexa, biconvexa plano-biconvexa R fruchartii cavernosa stenophylla microscopy studied trilayered tri layered depressions polysaccharides intine hand pectins organization endexine bryophytes

Resumo Os esporos de Riccia plano-biconvexa, R.fruchartii, R. cavernosa, R. stenophylla and R. curtisii foram analisados sob microscopia de luz. O estudo citoquímico foi realizado para distinguir as diferentes camadas do esporoderma e para determinar a sua natureza química. O esporoderma de todas as espécies estudadas apresenta uma exina com três camadas, composta por uma exina 1, lamelar, que forma cristas e depressões, uma exina 2, intermediária, e uma exina 3, espessa e geralmente descontínua. Os testes citoquímicos indicam que as exinas 1 e 2 são compostas por esporopolenina, enquanto a exina 3 é uma mistura de esporopolenina e polissacarídeos. A intina é a única camada só celulósica, além de conter pectinas. Com base na composição química e na organização estrutural, as exinas 1 e 2 podem ser agrupadas numa ectexina, enquanto a exina 3 corresponde a uma endexina. Nós ressaltamos a importância do uso de testes citoquímicos para o estudo da parede de esporos em hepáticas e outras briófitas. planobiconvexa, planobiconvexa plano biconvexa, biconvexa plano-biconvexa Rfruchartii R fruchartii R.fruchartii cavernosa luz lamelar depressões intermediária descontínua polissacarídeos celulósica pectinas estrutural ectexina endexina briófitas

RESUMEN En la Argentina la flora de antocerotes y hepáticas fue intensamente estudiada; sin embargo, la información de algunos grupos taxonómicos y su distribución geográfica dentro del país aún necesita ser actualizada o ampliada. El objetivo de este trabajo es dar a conocer nuevos registros tanto de antocerotes como de hepáticas para las cinco provincias que conforman la Patagonia argentina. El material seleccionado fue coleccionado, organizado y examinado de acuerdo con las técnicas tradicionalmente empleadas para las briofitas. Se incluye una lista comentada de las especies con notas sobre distribución y el material representativo examinado. Se presentan novedades de distribución para tres especies de antocerotes y 20 de hepáticas. Se menciona por primera vez para la provincia de Neuquén dos especies de antocerotes y ocho de hepáticas, seis hepáticas para Río Negro, un antocerote y dos hepáticas para Chubut, tres antocerotes y cuatro hepáticas para Santa Cruz y una hepática para Tierra del Fuego, Antártida e Islas del Atlántico Sur. Entre las especies encontradas, algunas se reportan para más de una provincia patagónica. Las numerosas novedades de distribución aquí presentadas demuestran la relevancia de continuar realizando estudios florísticos principalmente enfocados en la región sur del país.

ABSTRACT In Argentina, the flora of hornworts and liverworts was intensively studied; however, the information on some taxonomic groups and their geographic distribution within the country still needs to be updated or expanded. The objective of this work is to present new records of both hornworts and liverworts for the five provinces that are part Argentine Patagonia. The selected material was collected, organized and examined according to the techniques traditionally used for bryophytes. An annotated list of species is presented with notes on distribution and the representative material examined. Distribution novelties are presented for three hornwort species and 20 liverworts. Two species of hornworts and eight liverworts are mentioned for the first time for the province of Neuquén, six liverworts from Río Negro, one hornwort and two liverworts from Chubut, three hornworts and four liverworts from Santa Cruz, and one liverwort from Tierra del Fuego, Antártida e Islas del Atlántico Sur. Among the species found, some are reported for more than one Patagonian province. The numerous distribution novelties presented here demonstrate the importance of continuing to carry out floristic studies in the southern region of the country.

Abstract: Background and Aims: Ricciocarpos natans is one of the few species of truly aquatic hepatics. It has a subcosmopolitan distribution and appears to be more common in temperate areas. The species has been considered to be very rare in Central America where it was known only from Panama. The objective of this study is to report the presence of this species in Costa Rica and to survey its current distribution in Latin America. Methods: We provide an overview of the distribution of the floating aquatic liverwort Ricciocarpos natans in Latin America based on literature, herbarium specimens and unequivocal photographic records across the region, as well as field work in Costa Rica. Key results: Ricciocarpos natans is reported as new for Costa Rica. We provide the most complete survey to date of the geographic distribution of the species in Latin America. Conclusions: Our survey shows that Ricciocarpos natans appears to be more common and widely distributed in the Neotropics than previously assumed. Its assumed rarity seems to be the result of insufficient collection efforts.

Resumen: Antecedentes y Objetivos: Ricciocarpos natans es una de las pocas especies de hepáticas verdaderamente acuáticas. Tiene una distribución subcosmopolita y parece ser más común en áreas templadas. La especie ha sido considerada muy rara en América Central, donde solo se conocía de Panamá. El objetivo de este estudio es reportar la presencia de esta especie en Costa Rica y revisar su distribución en América Latina. Métodos: Brindamos una descripción general de la distribución de la hepática acuática flotante Ricciocarpos natans en América Latina con base en la literatura, especímenes de herbario y registros fotográficos inequívocos en toda la región, así como trabajo de campo en Costa Rica. Resultados clave: Ricciocarpos natans se reporta como nueva para Costa Rica. Brindamos el estudio más completo hasta la fecha de la distribución geográfica de la especie en América Latina. Conclusiones: Nuestro estudio muestra que Ricciocarpos natans parece ser más común y más ampliamente distribuida en el Neotrópico de lo que se suponía anteriormente. Su supuesta rareza parece ser el resultado de esfuerzos de recolección insuficientes.

RESUMEN Los briófitos forman un grupo conspicuo de la flora del planeta. Su contribución ecológica en términos de riqueza de especies y cobertura en muchos hábitats es fundamental para el equilibrio de los servicios ecosistémicos. En Colombia se tiene el registro aproximado de 715 especies de Marchantiophyta (hepáticas), las cuales presentan su mayor riqueza en la región Andina. El estudio se realizó en el Parque Nacional Natural Chingaza - sector Suasie dada su importancia ecológica e hídrica para los municipios aledaños. El objetivo principal de este estudio fue determinar la diversidad de la comunidad de hepáticas en el sector de Suasie del PNN Chingaza. Para ello, se hicieron tres levantamientos en transectos de 2x50 m en un gradiente altitudinal, en cada transecto se muestrearon las hepáticas presentes en cuatro forófitos escogidos al azar. Las muestras recolectadas fueron identificadas para el análisis de composición y diversidad de la comunidad. Como resultado, fue posible evidenciar la variación de la composición y abundancia de hepáticas a lo largo del gradiente, basados no solo en los índices estimados, sino también en la asociación con la cobertura vegetal de cada sitio de muestreo. Con un total de 47 especies registradas, se soporta la alta diversidad del sector en estudio. De esta manera, la riqueza encontrada en este gradiente aporta a las actuales y futuras estrategias de conservación del parque.

ABSTRACT The bryophytes form a conspicuous group of the planet's flora, their ecological contribution in terms of species richness and coverage in many habitats is essential for the balance of ecosystem. In Colombia there is an approximate record of 715 species of Marchantiophyta (liverworts), which present their greatest richness in the Andean region. The study was carried out in the Chingaza National Natural Park - Suasie sector given its ecological and water importance for the surrounding municipalities. The main objective of this study was to determine the diversity of the liverwort community in the Suasie sector of the Chingaza NNP. For this, three surveys were made in transects of 2x50 m in an altitude gradient, in each transect the liverworts present from four phorophytes (trees and shrubs), chosen at random were sampled. The collected samples were identified for analysis of composition and diversity of the community. As a result, it was possible to demonstrate the variation in the composition and abundance of liverworts along the gradient, based not only on the estimated indices, but also on the association with the vegetation cover of each sampling site. With a total of 47 registered species, the high diversity of the sector under study is supported. In this way, the richness found in this gradient contributes to current and future conservation strategies for the park.

ABSTRACT High-Altitude Fields are ecosystems with high bryophyte abundances and diversities. One of the principal threats to these ecosystems are wildfires, which mainly affect terricolous species. Chronosequence studies can aid in understanding post-fire effects on bryophytes. We studied terricolous assemblages of bryophytes in the High-Altitude Fields of Itatiaia National Park (INP) by establishing three 20x1 m transects in five areas: three areas of a post-fire chronosequence (treatments 2017, 2007, and 2001) and two control areas. We analyzed the species richness, floristic composition, life-forms, and floristic similarities of those transects, identifying 27 species of mosses (18 genera; 11 families) and 26 species of liverworts (20 genera; 16 families). Ditrichaceae was the principal moss family and Cephaloziellaceae the principal liverwort family. The life-forms encountered were turf (43 %), weft (38 %), thalloid (10 %), and mat (9 %). Turf predominated among mosses (85 %), and weft among liverworts (62 %). Species richness and floristic compositions varied among the post-fire gradients. The grouping dendrogram and ordination diagram evidenced greater similarity among transects within the same area. However, there was no evident gradient of floristic composition along the post-fire gradient, and further studies will be needed to quantify environmental gradients and their influences on bryophyte composition.

Resumen La especie Pleurozia paradoxa es una hepática de hábitat generalmente paramuno que se encuentra en estado vulnerable según el libro rojo de briófitas de Colombia debido a su poca presencia y su minúscula área de ocupación en el país. Mediante la aplicación de modelos de distribución de especies podemos estimar áreas de idoneidad que dan cuenta de la presencia probable de una especie. En este caso se usó un algoritmo de aprendizaje de máquinas denominado máxima entropía y el software Maxent, con el fin de obtener mapas de distribución potencial. Se emplearon varios registros de presencia y distintos juegos de variables climáticas para el modelamiento, además de un umbral de maximización de la especificidad y sensibilidad en el mapeo. Como resultado, la distribución potencial de P. paradoxa en Colombia se concentró en los departamentos del Cauca, Huila y Nariño a lo largo de la cordillera Central, extendiéndose levemente hacia el Valle del Cauca y Tolima, y en marcada relación con la altitud y el clima de dichas zonas.

Abstract Pleurozia paradoxa is a vulnerable liverwort from upper montane and paramo habitats in Colombia according to the Red Book of Bryophytes of Colombia due to its scarce presence and a small area of occupation in the country. Using species distribution models, it is possible to assess suitability areas accounting for the probable presence of species. We used a maximum entropy machine-learning algorithm to obtain potential distribution maps based on field records and climatic variables. The potential distribution of P. paradoxa in Colombia appeared to be concentrated in the Cordillera Central, departments of Cauca, Huila, and Nariño, extending slightly northwards to Valle del Cauca and Tolima, in strong correlation with altitude and climate.

Resumo O presente estudo teve como objetivo avaliar a distribuição espacial de briófitas ocorrentes na Ilha de Mosqueiro, na Amazônia. Foram selecionadas 41 parcelas de 100 m² em ambientes alagados e não alagados para coleta de dados. Os resultados foram comparados com os levantamentos de outras ilhas do estado do Pará e analisados segundo frequência de populações, substratos colonizados, guildas de tolerância à luz e distribuição nos biomas brasileiros. Foram registradas 97 espécies, distribuídas em 36 gêneros e 18 famílias, sendo 57 (58,7%) hepáticas e 40 (41,2%) espécies de musgo. As espécies raras se destacaram com 53 espécies (54,08%). Observou-se alta similaridade entre as comunidades corticícolas e epíxilas, e entre a comunidade terrícola e com as briófitas encontradas crescendo no carvão, que é um substrato artificial. Em relação às guildas de tolerância à luz, prevaleceu a espécie generalista (52 espécies, 53,6%). Quanto à distribuição fitogeográfica, houve predomínio de espécies com ocorrência na Amazônia e Mata Atlântica (35 espécies, 37,11%) e espécies endêmicas da Amazônia (10 espécies, 10,3%). Ceratolejeunea ceratantha é relatada pela primeira vez para o estado do Pará. O nível de antropização na ilha foi evidenciado principalmente pela alta riqueza e ocorrência de espécies generalistas e bem adaptadas às condições de estresse, evidenciando alterações na estrutura da comunidade de briófitas.

Abstract The present study is aimed to evaluate the richness, composition and spatial distribution of bryophytes occurring in Mosqueiro Island, in the Amazon forest. Forty-one 100-m² plots in 37 flooded and 4 non-flooded environments were selected for data collection, all substrate found were considered. The results were compared with surveys in other islands from the state of Pará and were analyzed according to frequency of populations, colonized substrates, light tolerance guilds, and distribution in Brazilian biomes. Ninety-seven species were recorded, distributed in 36 genera and 17 families, being 57 (58.7%) liverwort and 40 (41.2%) moss species. The rare species stood out with 53 species (54.08%). High similarity was observed between corticolous and epixylic communities, and between the terricolous community and the bryophytes found growing on charcoal, which is an artificial substrate. In relation to light tolerance guilds, generalist species prevailed (52 species, 53.6%). As for phytogeographic distribution, there was a predominance of taxa with occurrence in the Amazon and Atlantic rainforest (35 species, 37.11%). Ceratolejeunea ceratantha is reported for the first time for the state of Pará. The level of anthropization in the island was showed mainly by high richness and occurrence of generalist species underscores and well-adapted species to stressed conditions, evidencing changes in the bryophyte community structure.

Resumo Sphaerocarpos muccilloi (Sphaerocarpaceae, Marchantiophyta) foi descrito em 1981 como uma espécie endêmica e única da família no Brasil. É considerada Criticamente Ameaçada (CR) no estado do Rio Grande do Sul, Brasil, de acordo com a “Lista Vermelha das espécies da flora ameaçadas do estado do Rio Grande do Sul”. S. muccilloi é citado apenas para 3 localidades: Porto Alegre, São Leopoldo e Ivoti (coletado entre 1963 e 1977), todas áreas hoje altamente antropizadas, sendo a última coleta ocorrida há mais de 40 anos. Após uma revisão em herbários e coletas em campo S. muccilloi foi recoletado no ano de 2017 no Bioma Pampa (municípios de Santana do Livramento - Área de Proteção Ambiental do Ibirapuitã; Mata e Santa Vitória do Palmar). Outra espécie, Sphaerocarpos texanus, não registrada para o Brasil, foi reportada para o estado do Paraná. Estes novos registros fornecem importantes informações sobre a ocorrência e distribuição da família no Brasil. Para S. muccilloi, estes novos registros indicam que a distribuição desta espécie ameaçada é mais ampla. Estes dados subsidiarão a revisão da lista de espécies ameaçadas do Rio Grande do Sul e Brasil, além de subsidiar estratégias de conservação.

Abstract Sphaerocarpos muccilloi (Sphaerocarpaceae, Marchantiophyta) was described in 1981, being an endemic species and the only species of the family to Brazil. This species is considered as Critically Endangered (CR) according to “Red List of threatened species of the Rio Grande do Sul state”. Sphaerocarpos muccilloi was recorded in three places only in Rio Grande do Sul: Porto Alegre, São Leopoldo and Ivoti (collected from 1963 to 1977). These sites are highly anthropized and the last records being from more than 40 years. After a revision of herbarium specimens and several field trips we recollected S. muccilloi in the Pampa Biome, in Santana do Livramento municipality, at the Ibirapuitã Environmental Protection Area (APA do Ibaratuitã), Mata and Santa Vitória do Palmar municipalities. Another species (S. texanus), not reported to Brazil, was reported now to Paraná state. These new records provide important information about occurrence and distribution of the family to Brazil. Regarding to S. muccilloi, these new records show that the range of occurrence is wider than previous reported. This new data will help the next revision of the Red List of Threatened Species of Rio Grande do Sul and Brazil and will subsidize conservation strategies.

Resumen Muchas especies de briófitas tropicales crecen en habitats periódicamente inundados como lechos del río, pantanos y cascadas, pero se presentan pocos briófitas sumergidas permanentamente y están más que todo en lagunas de alta montaña. Su identificación podría ser dificil por la modificación de rasgos inducidos por el medio acuático. Aquí se trata de una población sumergida del género Herbertus de las hepáticas de una laguna glaciar a 4120 m en la Sierra Nevada del Cocuy, Colombia. Las plantas acuáticas caracterizadas por el porte enano y los apices obtusos de las hojas. Se ha identificado como H. oblongifolius, un taxon raro descrito de Brazil y recientemente, basado en la morfología, ubicada como sinónima de la especie variable, H. sendtneri, de distribución amplia. Análisis molecular ha confirmado que las plantas acuáticas pertenecen a H. sendtneri. La semejanza de las plantas acuáticas con las ramitas de H. sendtneri parece de sugerir un fenótipo juveníl. Las plantas acuáticas probablemente tienen su origen en una población en las rocas y lajas cercanas y han llegado a la laguna a través de ramitas vegetativas caedizas y así traidas a la laguna por el viento y el agua, o plantas enteras entraron a la laguna con lluvias fuertes inundando las lajas.

Abstract Many bryophytes grow in the Tropics in periodically inundated habitats such as river beds, marshes and waterfalls, but permanently submerged bryophytes are rare and are mainly found in high-altitude lakes. Their identification can be difficult due to modification of morphological traits induced by the aquatic environment. Here we deal with a submerged population of the liverwort genus Herbertus from a glacial lake at 4120 m the Sierra Nevada del Cocuy, Colombia. The aquatic plants, which stand out by dwarf statue and obtuse leaf tips, had been identified as H. oblongifolius, a rare taxon described from Brazil and recently placed in synonymy of the widespread and variable H. sendtneri based on morphology. Molecular analysis confirmed that the aquatic plants belong to H. sendtneri. The resemblance of the aquatic plants to small branches of H. sendtneri suggests that they might represent a juvenile phenotype. The aquatic plants probably originated from a rock-inhabiting population, which dispersed into the lake by means of vegetative reproduction via caducous branches or became washed into the lake. The dispersal event should have occurred during the last 12.000-21.000 years when the lake was ice-free.

RESUMEN Basado en nuestros estudios florísticos de briófitas en Colombia se registraron 15 especies de hepáticas nuevas para Colombia: Archilejeunea nebeliana, Colura calyptrifolia, Dibrachiella auberiana, Fossombronia fernandeziensis, Isopaches bicrenatus, Lejeunea angusta, L. concinnula, L. corynantha, L. galeata, L. pulverulenta, L. serpillifolioides, L. tapajosensis, Leptoscyphus hexagonus, Marchesinia languida y Riccia planobiconvexa. Se proporciona información del hábitat y distribución geográfica para todas las especies, así como también las diferencias taxonómicas. Lejeunea cochleata es un nuevo sinónimo de L. angusta y Taxilejeunea steyermarkii es un nuevo sinónimo de Lejeunea pulverulenta. Con unas 730 especies registradas, en 40 familias, Colombia es probablemente el país más rico en hepáticas en América tropical.

ABSTRACT Based on our ongoing studies of the bryophyte flora of Colombia we report 15 liverwort species new to the country: Archilejeunea nebeliana, Colura calyptrifolia, Dibrachiella auberiana, Fossombronia fernandeziensis, Isopaches bicrenatus, Lejeunea angusta, L. concinnula, L. corynantha, L. galeata, L. pulverulenta, L. serpillifolioides, L. tapajosensis, Leptoscyphus hexagonus, Marchesinia languida and Riccia planobiconvexa. Notes are provided on the distribution, habitat and taxonomic differentiation of the species. Lejeunea cochleata is a new synonym of L. angusta, and Taxilejeunea steyermarkii is a new synonym of Lejeunea pulverulenta. With 730 species recorded, in 40 families, Colombia is probably the richest country in liverworts in tropical America.

Cyathodium is a thalloid marchantialean liverwort with five species reported for the Neotropics. Three species that occur in Panama (C. bischlerianum, C. spruceanum, C. cavernarum) and one from Costa Rica (C. foetidissimum) were studied chemically. Female and male plants of the dioecious C. spruceanum were very similar in their chemical composition except for two compounds that were found only in female plants. All samples of C. spruceanum and C. bischlerianum contained, in less than three percent, the sesquiterpenes germacrene D and bicyclogermacrene. The presence of these compounds suggests a close affinity between these two species. Cyathodium bischlerianum contained mainly aromatic monoterpenes with nerolidol as the main compound. Cyathodium cavernarum also had a very distinct chemical composition with an octane derivative as its major compound. Indole compounds were found only in C. foetidissimum. The presence of these compounds in plants from Costa Rica and Tahiti suggests that they could be considered as potential chemosystematic markers for the species. Based on their chemical composition there is a clear distinction between the four species of Cyathodium studied. The chemistry of these species supports previous morphological and genetic studies. Only two compounds could be identified in Leiosporoceros dussii. There is a need for additional genetic and chemical studies on neotropical Cyathodium and Leiosporoceros.

Cyathodium es una hepática marchantial con cinco especies comunicadas para el Neotrópico. Se estudió la composición química de tres especies que crecen en Panamá (C. bischlerianum, C. spruceanum, C. cavernarum) y, una que crece en Costa Rica (C. foetidissimum). Plantas femeninas y masculinas del dioico C. spruceanum fueron muy similares en su composición química excepto por dos compuestos que se encontraron solo en plantas femeninas. Todas las muestras de Cyathodium spruceanum y C. bischlerianum contenían, en un porcentaje de menos del tres por ciento, los sesquiterpenos germacreno D y biciclogermacreno. La presencia de estos compuestos sugiere una afinidad muy cercana entre las dos especies. Cyathodium bischlerianum contiene principalmente monoterpenos aromáticos con nerolidol como el compuesto principal. Cyathodium cavernarum también tuvo una composición química muy distintiva con un derivado del octano como su compuesto principal. Compuestos de indol fueron encontrados solo en C. foetidissimum. La presencia de estos compuestos en plantas de Costa Rica y Tahiti sugiere que puedan ser marcadores quimosistemáticos para esta especie. Las cuatro especies de Cyathodium estudiadas se pueden distinguir de acuerdo con su composición química. La química de estas especies apoya estudios genéticos y morfológicos previos. Solo dos compuestos pudieron ser identificados en Leiosporoceros dussii. Se necesitan estudios genéticos y químicos adicionales para los Cyathodium y Leiosporoceros neotropicales.

We describe the new liverwort species Cheilolejeunea schiavoneana M.E.Reiner & Gradst. from submontane rainforest in the Western Cordillera of Colombia. The new species is related to C. adnata (C. sect. Cheilolejeunea) but differs by larger plant, leaf and underleaf size, robust stems, a 5-6 cells wide ventral merophyte, abundance of microphyllous branches, and vegetative reproduction by caducous leaf lobes produced on flagelliform shoots. The latter feature is characteristic of the genus Rectolejeunea and its presence in Cheilolejeunea is apparently a case of parallel evolution. The discovery of C. schiavoneana adds a further endemic taxon to the rich flora of the Colombian Western Cordillera.

Se describe la nueva especie Cheilolejeunea schiavoneana M.E.Reiner & Gradst., coleccionada en selva submontana de la Cordillera Occidental de Colombia. Este nuevo taxon está relacionado con C. adnata (C. sección Cheilolejeunea) pero difiere en el mayor tamaño de las plantas, hojas y anfigastrios, el ancho del merofito ventral (de 5-6 células), la abundancia de ramas microfilas, y la reproducción vegetativa por medio de lobos caducos producidos en tallos flagelíferos. Esta última propiedad es característica del género Rectolejeunea, y su presencia en Cheilolejeunea es aparentemente debida a evolución paralela. El descubrimiento de C. schiavoneana agrega otro taxon endémico a la gran diversidad de la flora en la Cordillera Occidental de Colombia.

ABSTRACT In bryophytes, establishment can occur by a sexual or asexual process, but the production of spores enables colonization of a wider range of habitats and substrates than can asexual propagules. Successful germination is critical for establishment in a new environment. This paper addresses germination and sporeling development in Frullania ericoides, a leafy liverwort species. Fresh spores were inoculated in vitro in different culture strengths of Knop’s nutrient solution (one-fourth strength, half strength, full strength, one and a half strength and double strength), in order to evaluate the effects of this solution on spore germination and on the development of external protonema. On the first assessment, spore germination was observed at all the concentrations. Germination was endosporic, with cell division and proliferation, resulting in a globular protonema, within the spore wall. Beginning at the fourth week, the development of tightly concave primordial leaves was observed in all but the double-strength medium. Throughout the period of study, the treatments with lower concentrations exhibited external protonema with greater lengths. The double-strength treatment was statistically different from other treatments in at least two parameters. The results of this study demonstrate the potential of in vitro culture techniques for bryophyte spore studies and germplasm preservation.

Abstract: The leafy liverwort flora from the Valley of Mexico has been less explored than the moss flora in the same region. There are no taxonomic, floristic or phytogeographic studies for this plant group, although in the literature there are sporadic reports. This contribution records 73 species, 1 variety and 1 subspecies of leafy liverworts that occur in the Valley of Mexico based on the review of the literature and examination of herbarium specimens. Lejeuneaceae (16 species) and Frullaniaceae (12 species) are the most diverse families of the region. A key and a brief description of each taxon are provided. Thirty one species recorded in the literature and/or found in herbarium collections at MEXU were not found in the field. Environmental degradation, lack of collecting in inaccessible areas, and inaccurate or incorrect data collection may account for their current absence.

Resumen: La flora de hepáticas del valle de México ha sido poco estudiada en comparación con la flora de musgos de la misma región. No hay trabajos taxonómicos, florísticos o fitogeográficos de hepáticas foliosas, aunque la literatura cita esporádicamente algunos ejemplares. En este estudio, con base en la revisión de la literatura, de ejemplares de herbario y de recolectas recientes, se registraron 73 especies, una variedad y una subespecie de hepáticas foliosas. Las Lejeuneaceae (16 especies) y las Frullaniaceae (12 especies) son las familias más diversas de la región. Esta contribución incluye una clave para la identificación y una breve descripción para cada taxón. Por otro lado, 31 especies registradas en la literatura y/o encontradas en los acervos de MEXU no fueron halladas en el campo. Es probable que la contaminación ambiental, la falta de recolecta en zonas inaccesibles o los datos históricos de colecta inexactos o incorrectos expliquen su ausencia actual.

Se presenta una clave taxonómica para los 130 géneros de hepáticas registrados en Colombia. Algunos géneros registradas de países vecinos, pero aún no de Colombia, también son incluidos.

A key is presented to 130 liverwort genera recorded from Colombia. Some genera found in neighboring countries, but not yet in Colombia, are also included in the key.