Scanning electron microscopy of gametophyte characters and antheridial opening in some Ceylonese species of Thelypteridaceae

Gametophytes of the fern family Thelypteridaceae were cultivated aseptically under controlled conditions and investigated with the scanning electron microscope. This report concerns six species, viz. Sphaerostephanos arbuscula S. subtruncatus, S. unitus, Macrothelypteris torresiana, Amauropelta hakgalensis and Pneumatopteris truncata . The gametophytes have some features in common. They are more or less heart-shaped and have glandular trichomes on surfaces and margins. In the middle is an elongated cushion bearing gametangia and rhizoids on the lower surface. Antheridia are of the type common to leptosporangiates, consisting of a basal cell, a ring cell and a cap cell. Archegonia consist externally of four rows of cells meeting at the top with triangular cells. The following features are distinguishing. The form of the margin of the thallus, type of hairiness, and the abundance of glandular hairs. Acicular hairs occur in Sphaerostephanos unitus and Pneumatopteris truncata . In Amauropelta hakgalensis the archegonium deviates from the common type in having a basal layer that consists of eight cells instead of four. In Macrothelypteris torresiana the four or three top cells are markedly irregular. In Sphaerostephanos arbuscula and Amauropelta hakgalensis the antheridial cap cell is sometimes divided. The manner of opening of antheridia and release of spermatozoids varies in each of the species investigated. This investigation reveals that it is possible to identify the species from gametophyte characters only.     

Sixteen new species of Thelypteris (Thelypteridaceae) from Bolivia

We describe 16 new species of Thelypteris (Thelypteridaceae) from Bolivia: T. aymarae, T. chaparensis, T. fasciola, T. fayorum, T. inaequilateralis, T. lumbricoides, T. madidiensis, T. minima, T. nephelium, T. parva, T. pelludia, T. pilonensis, T. rosulata, T. sapechoana, T. stephanii, and T. yungensis.     

New species and combinations in Thelypteris subg. Goniopteris (Thelypteridaceae)

Three new species ofThelypteris are described and illustrated:T. littoralis andT. paranaensis, endemic to the rainforest of the southern Brazilian Atlantic coast, andT. multigemmifera, endemic to inland gallery forests of the São Paulo state. In addition, four new combinations are made:T. cutiataensis (Brade) Salino,T. iguapensis (C. Chr.) Salino. A new name is proposed forDryopteris lugubris var.quadrangularis:T. montana Salino. The species treated here belong toThelypteris subg.Goniopteris due to the indument of furcate and stellate trichomes.     

Exploring generic delimitation within the fern family Thelypteridaceae

Thelypteridaceae is one of the largest families of polypodioid ferns. The generic classification of the family is still controversial because of high levels of convergent or parallel evolution of morphological characters and a lack of molecular phylogenetic studies. In the present study, phylogenetic analyses of three chloroplast regions (rbcL, rps4 and trnL-trnF intergenic spacer region) for 115 taxa, representing 27 recognized segregates in the family, were conducted to explore infrafamilial relationships and gain further understanding of generic boundaries. The phylogenetic reconstructions resolved six distinct clades (Clade I-VI) with strong support. Seven genera: Cyclogramma, Macrothelypteris, Oreopteris, Phegopteris, Pseudophegopteris, Stegnogramma, and Thelypteris are recognized from Clades I, II, IV, and V. In Clade III, Metathelypteris was supported as monophyletic, but the other segregates Amauropelta, Coryphopteris, and Parathelypteris were polyphyletic or paraphyletic, preventing clear recognition of generic boundaries within this clade without additional sampling. Considering great morphological homoplasy within Clade VI, a large genus Cyclosorus is recognized to comprise several small recognized segregates. Within this clade, Pronephrium, and Christella were revealed to be polyphyletic, but several Asian-endemic segregates, such as Glaphyropteridopsis, Mesopteris, and Pseudocyclosorus were strongly supported as monophyletic. Analyses of the evolution of morphological character states on the molecular phylogeny showed extremely high levels of homoplastic evolution for many diagnostic characters.     

On some species ofMycogloea

Three new species ofMycogloea are described and illustrated; they are:M. amethystina from Canada,M. nipponica, from Japan, andM. bullata from Thailand.Mycogloea tahitiensis is reported from Japan and additional undescribed taxa in the genus are briefly noted. Some characteristics of the genus are discussed, and a key is provided for six species recognized at this time.     

Induction of Biplanar Growth in Fern Gametophytes

In constant white light, protonemata of different ages of Asplenium nidus produce a fixed number of cells before they become biplanar. Protonemata with a lower initial cell number require a longer time to become biplanar than those with a higher initial cell number. Increasing the photoperiod or the light intensity reduces the cell number in the filament at the time of initiation of biplanar morphology. It is suggested that inductive light acts directly on cell metabolism to induce biplanar morphology, rather than indirectly by inducing mitotic activity.     

国产毛蕨属（金星蕨科）六新异名

将乐清毛蕨（ Cyclosorus luoqingensis ）处理为德化毛蕨（C．dehuaensis）的异名,南岭毛蕨（C．narlingensis）和少羽毛蕨（C．paucipinnus）处理为[梣]叶毛蕨（C．fraxinifolius）的异名,倒披针毛蕨（C．oblanceolatus）处理为南平毛蕨（C．nanpingensis）的异名,雁荡毛蕨（C．yandongensis）和寻乌毛蕨（C．xunwuensis）处理为华南毛蕨（C．parasiticus）的异名,并作了相应的讨论。     

Seeds and embryos in Sri Lanka (Ceylonese) species of Memecylon, with notes on Spathandra (Melastomataceae)

Seeds and embryos in 12 Ceylonese species of Memecylon are of three types with 1) cotyledons wrinkled and hypocotyl long, 2) cotyledons rolled and hypocotyl short, and 3) cotyledons fleshy and hypocotyl short. The first type is common in Memecylon and it occurs e.g. in M. capitellatum , the type species. The second type is found in M. arnottianum and M. gardneri as well as in some species of Spathandra , an African genus considered to be vaguely defined. The third type is new and it occurs in M. rivulare.     

Flavonoids of some species of Chrysosplenium

The flavonoid chemistry of eight species of Chrysosplenium has been established. The species studied were C. americanum, C. echinus, C. flagelliferum, C. glechomaefolium, C. iowense, C. rosendahlii, C. wrightii and C. valdivicum. The major compounds present were O-methylated flavones having an extra hydroxyl group at positions 6 and/or 2′ except for C. valdivicum which has isorhamnetin as its major flavonoid and only a trace of a compound bearing an extra hydroxyl group. Distribution of the O-methylated compounds in the genus correlates well with Franchet's sectional view of the genus wherein he recognized alternate-leaved vs opposite-leaved groups. The flavonoids of C. valdivicum represent a link between the more advanced members of the genus and other genera of the Saxifragaceae.     

Quantitative karyology of some species ofLuzula

The dimensions of metaphase chromosomes and nuclear DNA contents were measured in eight species ofLuzula. The 2 C DNA contents ranged from 8.51 pg inL. purpurea to 0.55 pg inL. pilosa. Total chromosome volume shows a linear relationship with DNA content; however, the total chromosome length of the complement of the different species is approximately constant. Nucleolar volume and the number of chromocentres in the different species also show a relationship with DNA content. Taken together, these data suggest that while chromosome fragmentation could have generated the present-day range of chromosome numbers in the genus, there have also been changes in the total quantity of DNA with the result that species with similar chromosome numbers have different DNA contents. The relationships of DNA content with chromosome volume inLuzula and other genera are compared and the differences discussed.