Three new hybrids of Ophioglossum (Ophioglossaceae) from Monte Pisano,Tuscany (Central Italy)

Based on general morphology, spore measurements and ornamentation (scanning electron microscope), genome size estimation, and molecular systematics (trnL-trnF IGS), we show the extreme systematic complexity within the European representatives of the genus Ophioglossum. In particular, three hybrids from Tuscany are described: the tetraploid O. × pierinii Peruzzi, Magrini, Marchetti & Viane, seen as the hybrid between diploid O. lusitanicum L. and hexaploid O. azoricum C.Presl; the tetraploid O. × giovanninii Peruzzi, Pierini, Magrini, Marchetti & Viane, seen as the homoploid hybrid between tetraploid O. vulgatum L. and tetraploid O. × pierinii Peruzzi, Magrini, Marchetti & Viane; the pentaploid O. × pseudoazoricum Peruzzi, Pierini, Magrini, Marchetti & Viane, seen as the hybrid between hexaploid O. azoricum C.Presl and tetraploid O. vulgatum L. All the three new taxa grow in different localities in the Monte Pisano mountain range.     

The Polymorphy of Fronds and Chromosome Number of Ophioglossum petiolatum Hook

A morphological and cytological study of a population of Ophioglossum petiolatum Hook. from the vicinity of Kunming, Yunnan Province was carried out. The fronds of this species are very variabte in. either size or figure. The outlines of laminae of different plants vary from narrowly lanceolate to ovate or broadly ovate (length: breadth can be from 6:1 to 1:1). The apices of laminae range from taper-pointed to acute or blunt, and the bases of laminae from attenuate to cuneate or nearly truncate. In most cases, the spore mother cells of the species have 480 bivalents at pro-meta- phase I of meiosis. The spores produced after normal meiosis are seemingly available. It shows that the species is an octoploid and probably sexual In few plants, many univalents at metaphase I of meiosis have also been seen, but we have failed to count their exact chromosome numbers. However, it reveals that there is a second cytotype in the population. From the fact that O. petiolatum has the great morphological variability and approximately constant chromosome number in a single population, the ecological conditions may not be the main reason of morphological variations of the Species. The high level of polyploidy and probable inbreeding system, the subterranean gametophytes must be hard to outcross, may give it a great ability of genetic lead which increases the genetic heterogeneity. and morphological varibility of populations. The voucher specimens are deposited inthe Herbarium of our Institute (PE). I am grateful to Prof. W. M. Chu of Yunnan University for his helpful suggestion and discuss.     

广西蕨类植物研究(1)

<正> 广西蕨类植物十分丰富,很早就引起了植物学家们的注意,并进行了大量的调查研究,积累了丰富的资料。近年来,在前辈们奠定的基础上,我们开始对广西蕨类植物进行较为系统的研究,以后将系列报道我们的研究意见。本文记载三个新分类群。     

Ultrastructural study of spore wall morphogenesis inOphioglossum thermale kom. var.nipponicum (Miyabe et Kudo) nishida

Spore wall morphogenesis ofOphioglossum thermale var.nipponicum was examined by transmission electron microscopy. The spore wall of this species consists of three layers: endospore, exospore, and perispore. The spore wall development begins at the tetrad stage. At first, the outer undulating lamellar layer of the exospore (Lo) is formed on the spore plasma membrane in advance of the inner accumulating lamellar layer (Li) of the exospore. Next, the homogeneous layer of the exospore (H) is deposited on the outer lamellar layer. Both lamellar layers may be derived from spore cytoplasm; and the homogeneous layer, from the tapetum. Then the endospore (EN) is formed. It may be derived from spore cytoplasm. The membranous perispore (PE), derived from the tapetum, covers the exospore surface as the final layer. Though the ornamentation of this species differs distinctly from that ofO. vulgatum, the results mentioned above are fundamentally in accordance with the data obtained fromO. vulgatum (Lugardon, 1971). Therefore, the pattern of spore wall morphogenesis appears to be very stable in the genusOphioglossum.     

Fate of epiphytes on phorophytes with different architectural characteristics along the perturbation gradient of Sabal mexicana forests in Veracruz,Mexico

Question: Vascular epiphytes and hemiepiphytes (E/HE) in neotropical forests account for a large fraction of plant richness, but little is known of how the interplay between phorophyte architectural characteristics and habitat perturbation affect communities of E/HE. Location: Sabal mexicana forests in a coastal area of Veracruz, Mexico. Methods: We compared communities of E/HE on phorophytes with different architectural characteristics – the palm S. mexicana and non‐palm phorophytes – in three environments: conserved sites, perturbed sites and small regenerated forest fragments. We combined traditional (abundance, species richness, similarity and complementarity indices) and more recent (phylogenetic diversity) metrics to describe the communities of E/HE. Results: Overall, we recorded 924 E/HE individuals (nine families, 16 genera and 21 species). The abundance and species richness of E/HE was higher on palms than on non‐palm phorophytes. Abundance‐based complementarities between phorophytes and sites were high. We detected clear changes in community structure of E/HE with habitat perturbation, but there were no effects on the phylogenetic diversity of the E/HE community. Palm phorophytes hosted a more phylogenetically diverse community of E/HE than did non‐palm phorophytes. Conclusions: Palm phorophytes are key elements supporting the conservation of resilient communities of E/HE in S. mexicana forest. Habitat fragmentation has a strong effect on the structure of the E/HE community in S. mexicana forests. Ferns are the group of epiphytes most severely affected by habitat perturbation, but we detected no significant effect on the phylogenetic diversity of the community.     

三峡库区淹没带2种濒危植物的新记录

近年来 ,笔者在调查三峡库区稀有濒危植物及地方特有植物的过程中 ,新发现 2种濒危植物在库区淹没带 1 ) 有分布。由于是永久性淹没 ,必然会造成该区这部分濒危植物种群及其生境的消失 ,应引起有关科研及保护部门的重视。以下就这 2种植物的分布、用途 ,在库区淹没带的生境、种群数量、伴生植物及在中国科学院武汉植物园的引种适应情况等进行介绍。1 　松叶蕨 Psilotum nudum(L.) Griseb.松叶蕨 Psilotum nudum( L.) Griseb.又名松叶兰 ,铁扫把 ,是国家第二批重点保护植物 [1 ,2 ] ,松叶蕨科 ( Psilotaceae)附生蕨类 ,分布于台湾、广东、…     

Untersuchungen über den Ursprung der fertilen Fieder vonOphioglossum pedunculosum

Observations of young leaf primordia give information about the origin of the fertile spike ofOphioglossum pedunculosum Desv. Each primordium shows a certain asymmetry that is visible in form and position of the fertile spike primordium, but above all in the course of the marginal meristem. The fertile spike primordium is connected with the marginal meristem on the right or that on the left side of the sterile segment. On the basis ot these observations the following concept of the origin of the fertile spike is formed: The marginal meristem curves on one side of the leaf primordium and turns towards the ventral side. This process is followed by meristem fractionation in the course of which the smaller part curved towards the middle of the leaf primordium becomes independent and initiates the development of the fertile spike, whereas the larger part of the marginal meristem contributes to the growth of the sterile segment.

     

Five new species of pteridophytes from Oaxaca,Mexico

Five new species are described from the state of Oaxaca in southern Mexico:Huperzia beiteliana Mickel,Ophioglossum dudadae Mickel,Selaginella basipilosa Valdespino,Selaginella mickelii Valdespino, andSelaginella nothohybrida Valdespino.