Embryology and embryogenesis of Spiranthes L.C.M. Richard (Orchidaceae): S. spiralis (L.) Cheval and S. aestivalis (Poiret) L.C.M. Richard

Abstract

The various stages of female gametophyte development and embryogenesis in S. spiralis and S. aestivalis are described. In both species the reproductive cycle is sexual. Some peculiarities are present: the female gametophyte is usually 6-7-8-nucleate; after double fertilization a single endospermatic cell is formed; the proembryo appears differentiated and is made up of different cells in the chalazal and micropylar ends; a single basal cell in the proembryo acts as suspensor.     

Rhus neoglutinosa sp. nov. (Anacardiaceae) and Teclea borenensis sp. nov. (Rutaceae) from Ethiopia.

Two new species, Rhus neoglutinosa M. Gilbert (Anacardiaceae) and Teclea borenensis M. Gilbert (Rutaceae) are described in preparation for the forthcoming Flora of Ethiopia.     

Dioecy in Fitzroya cupressoides (Molina) I.M. Johnst. and Pilgerodendron uviferum (D. Don.) Florin (Cupressaceae)

The aim of this study was to determine the dioecious or monoecious condition of Fitzroya cupressoides and Pilgerodendron uviferum. The study area lies west of the Nahuel Huapi National Park in northern Patagonia (Argentina), where these species form mixed stands. One hundred individuals of each species were studied over three successive years. The nature and position in the crown of their reproductive organs were recorded. Results showed that both species are dioecious. This feature has been confirmed on trees of these species growing in other sites within their natural distribution area in Argentina and Chile.     

A comparison of Dichodontium flavescens (Dicks.) Lindb. and D. pellucidum (Hedw.) Lindb. (Bryopsida)

Abstract

Fifty-three herbarium samples of the genus Dichodontium, originating from 15 countries in Europe and North America, were examined to critically assess new distinguishing characters between D. flavescens and D. pellucidum. The examination, including SEM, revealed some new characteristics in the gametophyte, notably leaf shape, leaf length: width ratio, and width of the nerve, permitting accurate determinations even on sterile material. D. flavescens is recognized here as a distinct species.     

The genus Hyalomma. VI. Systematics of H. (Euhyalomma) truncatum and the closely related species, H. (E.) albiparmatum and H. (E.) nitidum (Acari: Ixodidae)

The geographic distribution of three closely related Hyalomma species, namely Hyalomma (Euhyalomma) truncatum Koch, 1844, Hyalomma (Euhyalomma) albiparmatum Schulze, 1919 and Hyalomma (Euhyalomma) nitidum Schulze, 1919 is confined to Africa. A detailed comparison of all stages of development of the three taxa reveals that they possess many more shared than distinguishing characters. In fact differentiation between these species is based on single or dual qualitative characters on their adults. These are a conspicuous, ivory-coloured parma on H. (E.) albiparmatum males, and the absence or reduction in clarity of ivory-coloured bands on the leg segments of H. (E.) nitidum adults, as well as the shape of the external cuticular preatrial fold of the genital operculum of females of the latter species. The adults of all three species and the larva of H. (E.) truncatum are redescribed. The nymph of H. truncatum and the larva and nymph of H. (E.) albiparmatum and H. (E.) nitidum are described for the first time. Data on their geographic distributions and hosts are provided.     

Heliconema minnanensis n. sp. (Physalopteroidae: Physalopteridae) and Raphidascaris trichiuri (Yin and Zhang) n. comb. (Ascaridoidea: Anisakidae) in marine fishes.

Heliconema minnanensis n. sp. is described from the Chiloscyllium plagiosum south of the Minnan-Taiwan Bank Fishing Ground, Taiwan Strait. It is characterized by having the following combination of features. There are no longitudinal ridges in the posterior part of the body; the male has 4 pairs of precloacal papillae and 6-7 pairs of postcloacal papillae. The right spicule averages 0.2 mm long (1.1% of body length), and the left spicule averages 1.2 mm long (5.6% of body length), making an average spicule ratio of 1:5.2. The female has a vulva located on the left side of a thick membrane and 56-65% of the body length from the anterior end. Raphidascaris trichiuri (Yin and Zhang, 1983) comb. n., known previously from males only, is transferred from Cloeoascaris and redescribed, including material of both sexes from Muraenesox cinereus from the type locality.     

Alginate encapsulation of axillary buds of Ocimum americanum L. (hoary basil), O. Basilicum L. (sweet basil), O. Gratissimum L. (shrubby basil), and O. Sanctum. L. (sacred basil)

Summary Propagation and conservation of four pharmaceutically important herbs, Ocimum americanum L. syn. O. canum Sims. (hoary basil); O basilicum L. (swett basil); O. gratissimum L. (shrubby basil); and O. sanctum L. (sacred basil) was attempted using synthetic seed technology. Synthetic seeds were produced by encapsulating axillary vegetative buds harvested from garden-grown plants of these four Ocimum species in calcium alginate gel. The gel contained Murashige and Skoog (MS) nutrients and 1.1-4.4 μM benzyladenine (BA). Shoots emerged from the encapsulated buds on all six planting media tested. However, the highest frequency shoot emergence and maximum number of shoots per bud were recorded on media containing BA. Of the six planting media tested, both shoot and root emergence from the encapsulated buds in a single step was recorded on growth regulator-free MS medium as well as on vermi-compost moistened with halfstrength MS medium. Rooted shoots were retrieved from the encapsulated buds of O. americanum, O. basilicum, and O. sanctum on these two media, whereas shoots of O. gratissimum failed to root. The encapsulated buds could be stored for 60 d at 4°C. Plants retrieved from the encapsulated buds were hardened off and established in soil.     

Taxonomic notes on Cheilothela (Lindb.) Broth. and Dicranella (C. Muell.) Schimp.

Abstract

The widespread occurrence of a number of bryophytes on British saltmarshes is reported. The communities in which bryophytes are most frequently found are discussed. These communities are more common on marshes on the west coast of Britain. Differences between moss assemblages on salt marshes in England and Wales and in Scotland are emphasised and the greater range of habitat preference demonstrated by Grimmia maritima in Scotland is commented upon.     

Rhabditis (Rhabditis) freitasi sp.n. and Rhabditis (Rhabditis) costai sp.n. (Nematoda-Rhabditidae) isolated from bovine otitis

The author described two new species of Nematoda-Rhabditidae collected from the auditory meatus of catle with ear infection: Rhabditis (Rhabditis) freitasi sp.n. from Formosa county in the state of Goiás and Rhabditis (Rhabditis) costai sp.n. from Sert?ozinho county in the state of S?o Paulo.     

Notes on Stictocardia campanulata (L.) Merrill and S. Jucunda (Thw.) C. R. Gunn (Convolvulaceae)

The generic concept ofStictocardia is evaluated and accepted. Two species, whose nomenclature is interwoven withIpomoea alba andI. macrantha, are described, discussed, and illustrated.     

Maytenus eritreana sp. nov. and M. addat (Loes.) comb. nov. (Celastraceae) from northern Ethiopia

The new species Maytenus eritreana Sebsebe is described from northern Ethiopia. The new combination M. addat (Loes.) Sebsebe is made; this species occurs in the central and southern highlands of Ethiopia. The distribution of the two species is mapped.     

Sporophyte and gametophyte development of Platycerium coronarium (Koenig) Desv. and P. grande (Fee) C. Presl. (Polypodiaceae) through in vitro propagation

The sporophyte and gametophyte development of Platycerium coronarium and P. grande were compared through ex situ propagation using in vitro culture technique and under greenhouse and field conditions.The morphology of the sporophyte and gametophyte, type of spore germination and prothallial development of P. coronarium and P. grande were documented. Gametophytes of P. coronarium and P. grande were cultured in vitro using different media. The gametophytes were then transferred and potted in sterile chopped Cyathea spp. (anonotong) roots and garden soil for sporophyte formation. Sporophytes (plantlets) of the two Platycerium species were attached on the slabs of anonotong and on branches and trunks of Swietenia macrophylla (mahogany) under greenhouse and field conditions.Sporophyte morphology of P. coronarium and P. grande varies but not their gametophyte morphology. P. coronarium and P. grande exhibited rapid spore germination and gametophyte development in both spore culture medium and Knudson C culture medium containing 2% glucose. Gametophytes of P. coronarium and P. grande transferred to potting medium produced more number of sporophytes while the gametophytes inside the culture media did not produce sporophytes. Sporophytes of P. grande attached on mahogany branches produced more number of leaves with bigger leaf area than those attached on anonotong slabs. Likewise, sporophytes of P. coronarium attached on mahogany branches and anonotong slabs did not develop new leaves during two weeks monitoring and are still in a period of adjustment to its environment. Sporophytes of P. grande grown or attached on the trunk of mahogany trees in the field and under shaded environment favored their growth.     

N.m.r. and c.d. studies of the DNA fragments d(TATATATA) and d(TATATA) in solution

DNA fragments d(TATATATA) and d(TATATA) were studied in low-salt aqueous solutions and found to coexist in more than one conformer. 1H-n.m.r. demonstrates that single-stranded and double-stranded states are involved in the conformational coexistence. Circular dichroism spectroscopy indicates a global B-DNA stacking of bases in the fragments. 31P-n.m.r. resonances of the TpA and ApT phosphodiester bonds are substantially separated in the spectra of both d(TATATATA) and d(TATATA) duplexes to suggest an alternating architecture of their backbones. In fact, the oligonucleotide duplexes are much more alternating than the corresponding polynucleotide under the same solution conditions. The alternating character of the d(TATATATA) double helix is further enhanced in molar caesium fluoride solutions. The oligonucleotide isomerization into X-DNA is, however, accompanied by gel formation, which makes high resolution n.m.r. measurements impossible.     

Chromatin differentiation between Vigna radiata (L.) R. Wilczek and V. unguiculata (L.) Walp. (Fabaceae)

A comparative chromosomal evaluation was carried out between Vigna unguiculata (cowpea) and V. radiata (mung bean) with chromomycin A₃ (CMA₃)/4’,6-diamidino-2-phenylindole (DAPI) banding and fluorescent in situ hybridization (FISH) using 5S/45S ribosomal DNA (rDNA) probes. Both species had symmetric karyotypes (2n = 22), with prevalence of centromeres in chromosomes at median (m) and submedian (sm) regions and chromosomes ranging in size from 2.1 to 1.25 μm (V. unguiculata) and 2.18 to 0.93 μm (V. radiata). Three different banding patterns were identified for V. unguiculata: CMA₃⁺/DAPI⁰, CMA₃⁺⁺/DAPI^–, and CMA₃⁺/DAPI^–. The CMA₃⁺/DAPI⁰ bands were observed in the pericentromeric regions of all chromosomes, while the CMA₃⁺⁺/DAPI^– and CMA₃⁺/DAPI^– bands were co-localized with the 45S rDNA in the subtelomeric position (chromosomes B, G, and D, J, respectively) and in the proximal position in chromosome F. Two pairs of chromosomes (D and I) bearing interstitial 5S rDNA have been also identified. Vigna radiata displayed CMA₃⁰/DAPI⁺ bands distributed in the centromeric region of chromosomes B, C, and F, while CMA₃⁺⁺/DAPI^– bands were co-localized with the 45S rDNA sites in the subtelomeric position of the short arm in the F and K chromosome pairs. Three pairs of 5S rDNA sites were identified, the first in the proximal region of the long arm in chromosome E and the two others in the proximal and subterminal positions in the long arm of chromosome J. These data highlight some divergences regarding the amount and composition of the heterochromatin in both species, allowing the identification of individual chromosomes in V. unguiculata and V. radiata, and a comparison with other members of the Phaseoloid clade.     

Gynoecium and perianth inZanthoxylum s.l. (Rutaceae)

The question whether the uniseriate perianth ofZanthoxylum L. s. str. is homologous with the calyx or the corolla of taxa included inFagara, or of an independent origin, has been controversial for a long time, but the arguments mostly have remained theoretical. The present investigation of floral structures indicates that there are two different types of uniseriate perianth inZanthoxylum s. str. Therefore, this taxon does not represent a natural group and should be united withFagara asZanthoxylum s.l. The infrageneric taxonomy of this genus is still very ambiguous. It is shown that differences in indumentum, number of sepals and petals (5-4-3) resp. perianth segments (4–9), stamens (3–6), and free carpels (1–5) are of systematic relevance. Particularly important but so far neglected is carpel shape, where an acrostylous and an anacrostylous-basistylous type can be recognized. Stigmata of 2 or more carpels mostly fuse to form a compitum. 4–5-merous flowers with calyx and corolla, and acrostylous carpels are considered as plesiomorphic character states in the genus. On the basis of ± corresponding morphological and phytochemical progressions a working hypothesis about the relationships withinZanthoxylum s.l. is presented in graphical form (Fig. 9).Adapted from a lecture held at the 10th Symposion on Morphology, Anatomy, and Systematics in Göttingen, February 1991.