Pub Date : 2022-02-01DOI: 10.1640/0002-8444-112.1.50
Rongpei Yu, Yanfei Pu, Anthony E Baniaga, Shu-gang Lu, Guangfei Zhang
Abstract. Most species in the genus Selaginella (Selaginellaceae) are susceptible to desiccation, while a few species are able to withstand the extreme desiccation, recover metabolic functioning, and grow rapidly after rehydration. However, there is limited information about the anatomical features of the resurrection species in Selaginella. In the present study, we compared the microphyll micromorphology and ultrastructure of two resurrection species (S. pulvinata and S. sanguinolenta), and two non-resurrection species (S. kraussiana and S. chrysocaulos). Compared with the two non-resurrection species, the two resurrection species had most of their stomata distributed on the adaxial surface of microphylls that were tightly attached to stems, and possessed smaller and thicker microphylls, smaller stomatal size, higher stomatal density, thicker epidermal cell walls, more chloroplasts, and denser cytoplasm. These micromorphological and ultrastructural features of the two resurrection species were beneficial in reducing the transpiration and dehydration damage and could be considered as ecological adaptations to xeric environments.
{"title":"Comparative Micromorphology and Ultrastructure of Resurrection and Non-resurrection Selaginella Species","authors":"Rongpei Yu, Yanfei Pu, Anthony E Baniaga, Shu-gang Lu, Guangfei Zhang","doi":"10.1640/0002-8444-112.1.50","DOIUrl":"https://doi.org/10.1640/0002-8444-112.1.50","url":null,"abstract":"Abstract. Most species in the genus Selaginella (Selaginellaceae) are susceptible to desiccation, while a few species are able to withstand the extreme desiccation, recover metabolic functioning, and grow rapidly after rehydration. However, there is limited information about the anatomical features of the resurrection species in Selaginella. In the present study, we compared the microphyll micromorphology and ultrastructure of two resurrection species (S. pulvinata and S. sanguinolenta), and two non-resurrection species (S. kraussiana and S. chrysocaulos). Compared with the two non-resurrection species, the two resurrection species had most of their stomata distributed on the adaxial surface of microphylls that were tightly attached to stems, and possessed smaller and thicker microphylls, smaller stomatal size, higher stomatal density, thicker epidermal cell walls, more chloroplasts, and denser cytoplasm. These micromorphological and ultrastructural features of the two resurrection species were beneficial in reducing the transpiration and dehydration damage and could be considered as ecological adaptations to xeric environments.","PeriodicalId":50817,"journal":{"name":"American Fern Journal","volume":"112 1","pages":"50 - 72"},"PeriodicalIF":0.8,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46551528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-01DOI: 10.1640/0002-8444-112.1.1
Jerald B. Pinson, Sally M. Chambers, Emily B. Sessa
Abstract. Ferns and lycophytes are unique among land plants in having two independent life stages, the haploid gametophyte generation and the diploid sporophyte generation. While in most species the sporophyte is the dominant, long-lived portion of the life cycle, in some ferns the gametophyte is capable of sustained vegetative growth, and a number of species produce sporophytes only in parts of their geographic range (a pattern known as the separation of generations). One such species is the Hawaiian filmy fern Callistopteris baldwinii, whose growth form varies across elevational gradients. This species occurs as independent gametophytes near sea level, produces dwarfed sporophytes at mid elevations, and at the highest elevations—where precipitation is greatest due to the orographic uplift of trade winds—it grows as large, mature sporophytes. We measured temperature, relative humidity, and precipitation for several populations of this fern on the island of O‘ahu in Hawai‘i to determine whether these environmental factors may influence the spatial separation of generations exhibited by C. baldwinii on the island. Our results indicate that temperature and precipitation vary across life stages of C. baldwinii, underscoring the key role environmental conditions play in the completion of the fern life cycle.
{"title":"The Spatial Separation of Callistopteris baldwinii (Hymenophyllaceae) Sporophytes and Gametophytes Along Elevational Gradients in Hawai‘i","authors":"Jerald B. Pinson, Sally M. Chambers, Emily B. Sessa","doi":"10.1640/0002-8444-112.1.1","DOIUrl":"https://doi.org/10.1640/0002-8444-112.1.1","url":null,"abstract":"Abstract. Ferns and lycophytes are unique among land plants in having two independent life stages, the haploid gametophyte generation and the diploid sporophyte generation. While in most species the sporophyte is the dominant, long-lived portion of the life cycle, in some ferns the gametophyte is capable of sustained vegetative growth, and a number of species produce sporophytes only in parts of their geographic range (a pattern known as the separation of generations). One such species is the Hawaiian filmy fern Callistopteris baldwinii, whose growth form varies across elevational gradients. This species occurs as independent gametophytes near sea level, produces dwarfed sporophytes at mid elevations, and at the highest elevations—where precipitation is greatest due to the orographic uplift of trade winds—it grows as large, mature sporophytes. We measured temperature, relative humidity, and precipitation for several populations of this fern on the island of O‘ahu in Hawai‘i to determine whether these environmental factors may influence the spatial separation of generations exhibited by C. baldwinii on the island. Our results indicate that temperature and precipitation vary across life stages of C. baldwinii, underscoring the key role environmental conditions play in the completion of the fern life cycle.","PeriodicalId":50817,"journal":{"name":"American Fern Journal","volume":"112 1","pages":"1 - 16"},"PeriodicalIF":0.8,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47515910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-05DOI: 10.1640/0002-8444-111.4.251
M. Lehnert, A. Tejedor, Wilson D. Rodríguez Duque, Luis Fernando Giraldo Gallego
Abstract. We present an update to our knowledge of the taxonomically challenging Cyathea multiflora-group. Several taxa can be reinstated and newly described thanks to extensive field studies in Colombia and bordering countries. Easily overlooked characters like minute hairs, laminar squamules, and size of indusia correlate with distinct physiognomies in the field. Cyathea multiflora in the strict sense is almost restricted to Mesoamerica, just reaching into the Colombian Darién region. We observe a geographic overlap of several species especially in the Darién-Chocó region (Cyathea hildegardis sp. nov., C. pinnula, C. pinnuloides sp. nov., C. retanae) and two wider-ranging species extending from Mesoamerica into the Andes (C. acutidens, C. pinnula). The reinstated C. columbiana and newly recognized C. uregoana sp. nov. and C. prosopioides sp. nov. are restricted to the Chocó, including the Ecuadorean Esmeraldas region. Frequently found in the northern Colombian Cordillera central is C. paisa sp. nov., which is intermediate between C. pinnuloides of the Darién-Chocó region and C. lindigii, a relatively large species widespread in the Cordillera Oriental and the eastern Andean slopes south to Bolivia. We retain C. acutidens and C. leucolepismata as distinct species that can also be readily distinguished in the field by their appearance and the shape of the entire leaves but can be difficult to differentiate as fragmentary specimens. Cyathea mariposana sp. nov., a trunkless species presumably more closely related to C. squamulosa, is described from Panama. Cyathea retanae is reported from Colombia. A lectotype is chosen for C. columbiana. All relevant species are illustrated and incorporated in a diagnostic key.
摘要我们提出了一个更新的知识，我们的分类学挑战Cyathea multiflora-group。由于在哥伦比亚及其邻国进行了广泛的实地研究，一些分类群得以恢复和新描述。容易被忽视的特征，如微小的毛发、层流鳞片和工业的大小与该领域独特的地貌相关联。严格意义上的多花Cyathea multiflora几乎局限于中美洲，刚刚延伸到哥伦比亚的达里萨丹地区。我们观察到几个物种的地理重叠，特别是在Darién-Chocó地区(Cyathea hildegardis sp. nov.， C. pinnula, C. pinnuloides sp. nov.， C. retanae)和两个从中美洲延伸到安第斯山脉的更广泛的物种(C. acutdens, C. pinnula)。恢复的C. columbiana和新发现的C. uregoana sp. 11和C. prosopioides sp. 11仅限于Chocó，包括厄瓜多尔的Esmeraldas地区。经常在哥伦比亚北部科迪勒拉中部发现的是C. paisa sp. nov.，它介于Darién-Chocó地区的C. pinnuloides和C. lindigii之间，后者是一种相对较大的物种，广泛分布于科迪勒拉东部和安第斯山脉东部斜坡到玻利维亚南部。我们保留了C. acutdens和C. leucolepismata作为不同的物种，它们也可以很容易地在野外通过它们的外观和整个叶子的形状来区分，但作为碎片标本很难区分。Cyathea mariposana sp. nov.是一种无树干的物种，可能与C. squamulosa有更密切的关系，描述自巴拿马。据报道来自哥伦比亚。选择了一种选育型。所有相关的物种都被说明并纳入诊断关键。
{"title":"The Scaly Tree Ferns Allied to Cyathea multiflora (Cyatheaceae) in Colombia and Neighboring Countries","authors":"M. Lehnert, A. Tejedor, Wilson D. Rodríguez Duque, Luis Fernando Giraldo Gallego","doi":"10.1640/0002-8444-111.4.251","DOIUrl":"https://doi.org/10.1640/0002-8444-111.4.251","url":null,"abstract":"Abstract. We present an update to our knowledge of the taxonomically challenging Cyathea multiflora-group. Several taxa can be reinstated and newly described thanks to extensive field studies in Colombia and bordering countries. Easily overlooked characters like minute hairs, laminar squamules, and size of indusia correlate with distinct physiognomies in the field. Cyathea multiflora in the strict sense is almost restricted to Mesoamerica, just reaching into the Colombian Darién region. We observe a geographic overlap of several species especially in the Darién-Chocó region (Cyathea hildegardis sp. nov., C. pinnula, C. pinnuloides sp. nov., C. retanae) and two wider-ranging species extending from Mesoamerica into the Andes (C. acutidens, C. pinnula). The reinstated C. columbiana and newly recognized C. uregoana sp. nov. and C. prosopioides sp. nov. are restricted to the Chocó, including the Ecuadorean Esmeraldas region. Frequently found in the northern Colombian Cordillera central is C. paisa sp. nov., which is intermediate between C. pinnuloides of the Darién-Chocó region and C. lindigii, a relatively large species widespread in the Cordillera Oriental and the eastern Andean slopes south to Bolivia. We retain C. acutidens and C. leucolepismata as distinct species that can also be readily distinguished in the field by their appearance and the shape of the entire leaves but can be difficult to differentiate as fragmentary specimens. Cyathea mariposana sp. nov., a trunkless species presumably more closely related to C. squamulosa, is described from Panama. Cyathea retanae is reported from Colombia. A lectotype is chosen for C. columbiana. All relevant species are illustrated and incorporated in a diagnostic key.","PeriodicalId":50817,"journal":{"name":"American Fern Journal","volume":"111 1","pages":"251 - 307"},"PeriodicalIF":0.8,"publicationDate":"2021-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47918790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-05DOI: 10.1640/0002-8444-111.4.327
N. V. Campos, S. L. Cavalheiro-Filho, Laís B. Jordão, F. Santos, A. Castilho, R. Martins, Francisco A. Esteves, L. Gestinari
{"title":"Discovery of Mixed Sporangia in the Amazonian Quillwort Isoëtes cangae","authors":"N. V. Campos, S. L. Cavalheiro-Filho, Laís B. Jordão, F. Santos, A. Castilho, R. Martins, Francisco A. Esteves, L. Gestinari","doi":"10.1640/0002-8444-111.4.327","DOIUrl":"https://doi.org/10.1640/0002-8444-111.4.327","url":null,"abstract":"","PeriodicalId":50817,"journal":{"name":"American Fern Journal","volume":"3 11","pages":"327 - 331"},"PeriodicalIF":0.8,"publicationDate":"2021-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41256658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-05DOI: 10.1640/0002-8444-111.4.223
Keegan Heron, M. Windham, D. Farrar, K. Pryer
Abstract. Glacier National Park encompasses over one million acres in the mountains of northwestern Montana, along the United States–Canada border. Our survey of online databases indicates that the earliest extant fern and lycophyte collections from this area were taken by Robert S. Williams in 1892. In the summer of 1919, Paul C. Standley, a botanist with the United States National Museum, conducted a survey of the flora of the newly created Park and recorded 39 species of ferns and lycophytes. In 2002, a revised flora for the Park by Peter Lesica increased this number to 61. Here we summarize 130 years of collections-based research on the ferns and lycophytes of Glacier National Park, documenting how our understanding of the flora has changed through time. In the summer of 2019, the lead author conducted a field survey to relocate as many ferns and lycophytes as possible within park boundaries. In parallel, we scoured herbarium online portals and databases for high-resolution digitized specimen images to confirm or refute historical vouchers of ferns and lycophytes collected from the Park. In a few cases, specimen loans were requested from herbaria to confirm our determinations. The results from our combined field and online herbarium studies are presented here. Of the 61 taxa recognized by Lesica in 2002, we were able to confirm all but seven. In sum, we recognize here a total of 71 fern and lycophyte taxa for the Park. Most previously unreported taxa belong to Botrychium, a genus that has seen a flurry of recent taxonomic work by co-author Farrar and collaborators. These new data are presented here together with updated nomenclature and discussion to provide a current taxonomic account of the fourteen fern and lycophyte families known to occur in Glacier National Park. We anticipate this study will provide a useful foundation for further investigations in the Park.
{"title":"Looking Back on 130 Years of Fern and Lycophyte Research in Glacier National Park, Montana: A Modern Taxonomic Account","authors":"Keegan Heron, M. Windham, D. Farrar, K. Pryer","doi":"10.1640/0002-8444-111.4.223","DOIUrl":"https://doi.org/10.1640/0002-8444-111.4.223","url":null,"abstract":"Abstract. Glacier National Park encompasses over one million acres in the mountains of northwestern Montana, along the United States–Canada border. Our survey of online databases indicates that the earliest extant fern and lycophyte collections from this area were taken by Robert S. Williams in 1892. In the summer of 1919, Paul C. Standley, a botanist with the United States National Museum, conducted a survey of the flora of the newly created Park and recorded 39 species of ferns and lycophytes. In 2002, a revised flora for the Park by Peter Lesica increased this number to 61. Here we summarize 130 years of collections-based research on the ferns and lycophytes of Glacier National Park, documenting how our understanding of the flora has changed through time. In the summer of 2019, the lead author conducted a field survey to relocate as many ferns and lycophytes as possible within park boundaries. In parallel, we scoured herbarium online portals and databases for high-resolution digitized specimen images to confirm or refute historical vouchers of ferns and lycophytes collected from the Park. In a few cases, specimen loans were requested from herbaria to confirm our determinations. The results from our combined field and online herbarium studies are presented here. Of the 61 taxa recognized by Lesica in 2002, we were able to confirm all but seven. In sum, we recognize here a total of 71 fern and lycophyte taxa for the Park. Most previously unreported taxa belong to Botrychium, a genus that has seen a flurry of recent taxonomic work by co-author Farrar and collaborators. These new data are presented here together with updated nomenclature and discussion to provide a current taxonomic account of the fourteen fern and lycophyte families known to occur in Glacier National Park. We anticipate this study will provide a useful foundation for further investigations in the Park.","PeriodicalId":50817,"journal":{"name":"American Fern Journal","volume":"111 1","pages":"223 - 250"},"PeriodicalIF":0.8,"publicationDate":"2021-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43577461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-05DOI: 10.1640/0002-8444-111.4.308
J. Watts, J. E. Watkins
Abstract. Plants are characterized by their marked plasticity and ability to alter their functional biology to partition ecological niches. However, there are limits to functional trait exploration especially in complex and stressful habitats. Highly specialized traits may control a species ability to explore within and across habitats. Such may be especially true of epiphytes, whose array of unique traits may constrain their ability to cross establish in epiphytic and terrestrial habitats. In the case of ferns, there are few reported examples of species that can grow across these habitats with regularity. However, this study reports and explores species that exhibit great ecological flexibility growing across a wide range of habitats and growth forms. Specifically, we examine species that grow as 1) terrestrially rooted and epiphytic individuals, 2) nest and non-nest-forming epiphytes; and nest-forming terrestrially rooted individuals, and 3) species that grow as terrestrial, epiphytic, and epipetric individuals. We use natural abundance foliar stable isotope ratios (SIR) of N15 and C13, and %N, to explore intraspecific variation in mineral nutrition and water relations across and within niches. Our results reveal the 1) unreported ability of some species to grow across the epiphytic/terrestrial divide, 2) surprising ability of some species to explore these habitats with little to no shift in functional traits; 3) a potentially new function for the nest in nest-forming epiphytes. Finally, our work highlights the need to consider intraspecific trait variation more carefully when studying ferns that occur across a wide range of habitats.
{"title":"Crossing the Divide: An Exploration of Functional Traits in Ferns that Grow Across Terrestrial, Epipetric, and Epiphytic Habitats","authors":"J. Watts, J. E. Watkins","doi":"10.1640/0002-8444-111.4.308","DOIUrl":"https://doi.org/10.1640/0002-8444-111.4.308","url":null,"abstract":"Abstract. Plants are characterized by their marked plasticity and ability to alter their functional biology to partition ecological niches. However, there are limits to functional trait exploration especially in complex and stressful habitats. Highly specialized traits may control a species ability to explore within and across habitats. Such may be especially true of epiphytes, whose array of unique traits may constrain their ability to cross establish in epiphytic and terrestrial habitats. In the case of ferns, there are few reported examples of species that can grow across these habitats with regularity. However, this study reports and explores species that exhibit great ecological flexibility growing across a wide range of habitats and growth forms. Specifically, we examine species that grow as 1) terrestrially rooted and epiphytic individuals, 2) nest and non-nest-forming epiphytes; and nest-forming terrestrially rooted individuals, and 3) species that grow as terrestrial, epiphytic, and epipetric individuals. We use natural abundance foliar stable isotope ratios (SIR) of N15 and C13, and %N, to explore intraspecific variation in mineral nutrition and water relations across and within niches. Our results reveal the 1) unreported ability of some species to grow across the epiphytic/terrestrial divide, 2) surprising ability of some species to explore these habitats with little to no shift in functional traits; 3) a potentially new function for the nest in nest-forming epiphytes. Finally, our work highlights the need to consider intraspecific trait variation more carefully when studying ferns that occur across a wide range of habitats.","PeriodicalId":50817,"journal":{"name":"American Fern Journal","volume":"111 1","pages":"308 - 326"},"PeriodicalIF":0.8,"publicationDate":"2021-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43548060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-02DOI: 10.1640/0002-8444-111.3.205
Wataru Shinohara, L. Perrie, N. Murakami
Abstract. Histiopteris incisa (Dennstaedtiaceae) is one of the most cosmopolitan species among the leptosporangiate ferns. Based on sequences of the chloroplast rbcL gene, we recognize two lineages within H. incisa, and these differ in scale and leaf morphology. This suggests that at least two evolutionarily distinct species are contained within present circumscriptions of H. incisa.
{"title":"At Least Two Evolutionarily Distinct Species within Histiopteris incisa Inferred from Molecular and Morphological Evidence","authors":"Wataru Shinohara, L. Perrie, N. Murakami","doi":"10.1640/0002-8444-111.3.205","DOIUrl":"https://doi.org/10.1640/0002-8444-111.3.205","url":null,"abstract":"Abstract. Histiopteris incisa (Dennstaedtiaceae) is one of the most cosmopolitan species among the leptosporangiate ferns. Based on sequences of the chloroplast rbcL gene, we recognize two lineages within H. incisa, and these differ in scale and leaf morphology. This suggests that at least two evolutionarily distinct species are contained within present circumscriptions of H. incisa.","PeriodicalId":50817,"journal":{"name":"American Fern Journal","volume":"111 1","pages":"205 - 213"},"PeriodicalIF":0.8,"publicationDate":"2021-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44060126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-02DOI: 10.1640/0002-8444-111.3.196
S. Molino, Michael A. Sundue, W. Testo
Abstract. Sporangiasters are an uncommon type of paraphyses, occurring in a handful of leptosporangiate fern genera. We report sporangiasters in Parablechnum nesophilum, which is their first recorded occurrence in the Blechnaceae. We provide evidence of their homology to sporangia and discuss their functional significance. The presence of sporangiasters in P. nesophilum is surprising because the species has a well-developed indusium, and paraphyses are generally most common in exindusiate ferns. We surmise that these sporangiasters act as a second stage of protection for the developing sporangia after the indusium retracts. Alternatively, it is possible that sporangiasters may influence the vagility of spores by inhibiting dehiscence and limiting the ability of the annulus to disperse its spores.
{"title":"First Record of Sporangiasters in the Blechnaceae","authors":"S. Molino, Michael A. Sundue, W. Testo","doi":"10.1640/0002-8444-111.3.196","DOIUrl":"https://doi.org/10.1640/0002-8444-111.3.196","url":null,"abstract":"Abstract. Sporangiasters are an uncommon type of paraphyses, occurring in a handful of leptosporangiate fern genera. We report sporangiasters in Parablechnum nesophilum, which is their first recorded occurrence in the Blechnaceae. We provide evidence of their homology to sporangia and discuss their functional significance. The presence of sporangiasters in P. nesophilum is surprising because the species has a well-developed indusium, and paraphyses are generally most common in exindusiate ferns. We surmise that these sporangiasters act as a second stage of protection for the developing sporangia after the indusium retracts. Alternatively, it is possible that sporangiasters may influence the vagility of spores by inhibiting dehiscence and limiting the ability of the annulus to disperse its spores.","PeriodicalId":50817,"journal":{"name":"American Fern Journal","volume":"111 1","pages":"196 - 204"},"PeriodicalIF":0.8,"publicationDate":"2021-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41678040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-02DOI: 10.1640/0002-8444-111.3.174
S. L. Cavalheiro-Filho, L. Gestinari, T. Konno, M. P. Santos, E. Calderon, Mariana C. H. Marques, F. M. D. Dos Santos, A. Castilho, R. Martins, F. Esteves, N. V. Campos
Abstract. Isoëtes cangae and Isoëtes serracarajensis (Isoetaceae) are species endemic to Carajás (Pará State, Brazil) that grow on iron-rich substrates of the Amazon basin under a seasonal rainfall regime. In addition to a few distinctive morphological traits, the species differ in terms of habitat and geographical distribution. The influence of the seasonality and habitat characteristics on quillwort morphology is poorly understood. To assess this influence, specimens from one population of I. cangae, and four populations of I. serracarajensis, were sampled in dry and rainy seasons to investigate variation among vegetative and reproductive characters. The megasporangium color, megaspore ornamentation, alae length, velum length and coverage (%), morphometry of sporangial wall cells, and polar/equatorial diameter ratio of megaspores provide consistent characters for species delimitation. The presence of stomata in I. serracarajensis is a new discovery and is related to its amphibious habit. Some characters that have been used in Isoëtes species descriptions, such as the number of leaves, leaf length, sporangium size, number of megaspores, and megaspore diameter were found to be variable. The current findings provide further information on the biology of the species and show the influence of seasonality and habitat characteristics on the morphological diversity of these lycophytes.
{"title":"Morphological Plasticity in the Endemic Isoëtes Species from Serra dos Carajás, Amazonia, Brazil","authors":"S. L. Cavalheiro-Filho, L. Gestinari, T. Konno, M. P. Santos, E. Calderon, Mariana C. H. Marques, F. M. D. Dos Santos, A. Castilho, R. Martins, F. Esteves, N. V. Campos","doi":"10.1640/0002-8444-111.3.174","DOIUrl":"https://doi.org/10.1640/0002-8444-111.3.174","url":null,"abstract":"Abstract. Isoëtes cangae and Isoëtes serracarajensis (Isoetaceae) are species endemic to Carajás (Pará State, Brazil) that grow on iron-rich substrates of the Amazon basin under a seasonal rainfall regime. In addition to a few distinctive morphological traits, the species differ in terms of habitat and geographical distribution. The influence of the seasonality and habitat characteristics on quillwort morphology is poorly understood. To assess this influence, specimens from one population of I. cangae, and four populations of I. serracarajensis, were sampled in dry and rainy seasons to investigate variation among vegetative and reproductive characters. The megasporangium color, megaspore ornamentation, alae length, velum length and coverage (%), morphometry of sporangial wall cells, and polar/equatorial diameter ratio of megaspores provide consistent characters for species delimitation. The presence of stomata in I. serracarajensis is a new discovery and is related to its amphibious habit. Some characters that have been used in Isoëtes species descriptions, such as the number of leaves, leaf length, sporangium size, number of megaspores, and megaspore diameter were found to be variable. The current findings provide further information on the biology of the species and show the influence of seasonality and habitat characteristics on the morphological diversity of these lycophytes.","PeriodicalId":50817,"journal":{"name":"American Fern Journal","volume":"111 1","pages":"174 - 195"},"PeriodicalIF":0.8,"publicationDate":"2021-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49641907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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