Three New Species of Nothacrobeles (Nemata: Cephalobidae) from the Mojave Desert, California

Three new species of Nothacrobeles are described from localities in the Mojave Desert, southern California. Nothacrobeles triniglarus n. sp. is characterized by the presence of a long post-vulval sac and three tubular adoral projections. Both N. spatulatus n. sp. and N. nanocorpus n. sp. are smaller than any other known species within the genus. Nothacrobeles spatulatus n. sp. has labial probolae that are short and spatulate without a basal ridge, whereas those of N. nanocorpus n. sp. are flattened and plate-like. Furthermore, N. nanocorpus n. sp. is unique by its extremely short esophageal corpus (less than 25 µm long in adult females) and the small size of its guard processes. An emended diagnosis of the genus is given to accommodate distinctive characteristics of these new species. A table comparing the 11 valid species of Nothacrobeles is presented.     

The relation of carbon dioxide compensation and chlorenchymatous vascular bundle sheaths in leaves of dicots

Low CO₂ compensation points have been found to be associated with several unusual characteristics related to photosynthesis. One such characteristic is a prominent, chlorenchymatous vascular bundle sheath in the leaves. It has been suggested that the presence of this sheath in dicotyledons can serve as a means of detecting low CO₂-compensating species. We collected 88 dicotyledon species from 22 families reported to have chlorenchymatous sheaths. Of the 88, only three, Tribulus terrestris, L., Boerhaavia paniculata, L. C. Rich, and Trianthema portulacastrum L., had low CO₂ compensation points. Cross sections of the leaves of the other species revealed that they did have chlorenchymatous vascular bundle sheaths. However, these sheath cells contained chloroplasts which were not specialized for starch formation as were the bundle sheath chloroplasts of the low CO₂-compensating species.     

Taxonomic study onSargassum sagamianum Yendo and related species (phaeophyta,fucales)

The taxon currently known asSargassum sagamianum is shown to include forms that are distinguishable from each other at specific level.S. sagamianum Yendo (sensu stricto) has a conical holdfast, branched upright stem, main branches triquetrous with sharp edges, leaves with sparsely serrate margins, and triquetrous female receptacles which mature in autumn.S. yamadae Yoshida et T. Konno spec. nov. has a creeping stem adhering to the substratum by attaching discs forming later a solid discoid holdfast, and simple spatulate receptacles which mature in spring to early summer.S. okamurae Yoshida et T. Konno spec. nov. is characterized by a creeping stem adhering by small attaching discs, its flat branches, linear lanceolate leaves with entire margins, and forked receptacles which mature in late autumn.S. yezoense (Yamada) Yoshida et T. Konno stat. nov. is considered as a distinct species with its creeping stem with a few attaching discs, its leaves not retroflexed, by its main branch having rounded edges, and simple spatulate receptacles maturing in summer.     

中国菊属一新变种

报道了中国菊属(Chrysanthemum)一新变种——阔叶毛华菊(Chrysanthemum vestitum(Hem sl.)Stapf.var.latifolium J.Zhou et J.Y.Chen)。本变种与模式变种的区别在于直立生长,并且较多分枝,叶较狭,卵状披针形或匙形,长4~6 cm,宽2~3 cm。花序直径较原种为小,约3.5~4.5 cm。主要分布于湖北宜昌、河南伏牛山山脉。抗旱性较原变种强。而主要原产于安徽西部大别山麓之模式变种则铺散生长,较少分枝,叶圆形、卵圆形,长4~7cm,宽3~5 cm。花序直径较大,约4.5~5.0 cm。     

Morphology, anatomy and vasculature of leaves in Pinus (Pinaceae) and its evolutionary meaning

The morphology, anatomy and vasculature of Pinus leaves was studied. The results indicate that the Pinus leaf is always supplied with only one single vascular bundle, which is surrounded by a prominent bundle sheath. In several taxa, especially of subgenus Pinus, the vascular bundle may however be subdivided by longitudinal parenchymatic bands in the middle part of the leaf. As a result, the single bundle gets the appearance of two individual bundles, which are surrounded by a common bundle sheath. The general rule that a bundle sheath does sheath only one single bundle, as in other gymno- and angiospermous seed plants, applies therefore also for Pinus. The morphological and anatomical similarities between cladodes of Sciadopitys (Sciadopityaceae) and Pinus leaves are based on a completely different bauplan. The idea of “hidden cladodes” in some Pinaceae is therefore obsolete.     

The ramification of Apinagia riedelii: A key to the understanding of the plant architecture of Podostemaceae,subfamily Podostemoideae

The study of the ramification pattern of Apinagia riedelii results in a new concept of the architecture of this species, with general implications to members of subfamily Podostemoideae with dithecous leaves. The presence of a subtending leaf below the floriferous shoot proves axillary branching also for species with dithecous leaves. Previous opinions of an unusual ramification mode by subfoliar or non-axillary branching or stem bifurcation in combination with dithecous leaves hitherto pleaded for Podostemoideae is refuted. Moreover, the view of the so-called dithecous leaves with one sheath (theca) at the ventral and one at the dorsal side of the leaf, previously regarded as initially connected with branching, has to be changed. The dithecous leaf arises from the branch and not from the mother shoot axis – as previously believed – and represents the addorsed hypsophyll, i.e., the first leaf (prophyll) of the floriferous branch. This finding leads to the conclusion that the lower sheath of the dithecous leaf is the ventral (not dorsal) sheath pointing to the branch and surrounding its flower bud with a ligule or an ochrea and a hood upon the bud. In this way, the branch and its flower bud become seemingly sunk in the leaf base. At the fusion of leaf basis and shoot results this enigmatic common tissue. The wings of the dorsal (upper) sheath of the dithecous leaf point to the mother shoot axis of the branch. Successive floriferous branches along the main stem disclose the shoot axis of A. riedelii as a monopodium (not sympodium) that develops an anthocladial (foliated) inflorescence in the form of a botrys or a compound botrys, respectively. Since it is generally difficult to define cymose or racemose inflorescences if subtending leaves are absent – which occur in most other species of subfamily Podostemoideae with dithecous leaves – the nature of these inflorescences is discussed anew. The findings on A. riedelii have consequences on our comprehension of the shoot architecture of Podostemoideae.     

Gazania lanata and G. splendidissima: Two new species of Asteraceae (tribe Arctotideae) from the Greater Capensis, with an updated key for the genus

Two new species of Gazania Gaert. (Asteraceae, tribe Arctotideae) from the Greater Cape Floristic Region of South Africa are described. Gazania lanata Magee & Boatwr., a local endemic of dolomite lenses near Robertson, is distinguished by the spatulate to sublyrate, simple or weakly pinnatilobed leaves, the bristle-like hairs along the inflorescence and the densely lanate vestiture of the young growth and involucre. Gazania splendidissima Mucina, Magee & Boatwr. from the arid Namaqualand coast between Port Nolloth and Hondeklipbaai, is distinguished by the suffrutescent habit, semi-succulent leaves with a densely mealy uppermost surface, and prominently maculate involucre. An updated key to the now 18 recognised Gazania species is provided to facilitate identification of these and existing taxa in the genus.     

Inaccessible Biodiversity on Limestone Cliffs: Aster tianmenshanensis (Asteraceae), a New Critically Endangered Species from China

Aster tianmenshanensis G. J. Zhang & T. G. Gao, a new species of Asteraceae from southern China is described and illustrated based on evidence from morphology, micromorphology and molecular phylogeny. The new species is superficially similar to Aster salwinensis Onno in having rosettes of spatulate leaves and a solitary, terminal capitulum, but it differs by its glabrous leaf margins, unequal disc floret lobes and 1-seriate pappus. The molecular phylogenetic analysis, based on nuclear sequences ITS, ETS and chloroplast sequence trnL-F, showed that the new species was nested within the genus Aster and formed a well supported clade with Aster verticillatus (Reinw.) Brouillet et al. The new species differs from the latter in having unbranched stems, much larger capitula, unequal disc floret lobes, beakless achenes and persistent pappus. In particular, A. tianmenshanensis has very short stigmatic lines, only ca. 0.18 mm long and less than 1/3 of the length of sterile style tip appendages, remarkably different from its congeners. This type of stigmatic line, as far as we know, has not been found in any other species of Aster. The very short stigmatic lines plus the unequal disc floret lobes imply that the new species may have a very specialized pollination system, which may be a consequence of habitat specialization. The new species grows only on the limestone cliffs of Mt. Tianmen, Hunan Province, at the elevation of 1400 m. It could only be accessed when a plank walkway was built across the cliffs for tourists. As it is known only from an area estimated at less than 10 km² and a walkway passes through this location, its habitat could be easily disturbed. This species should best be treated as Critically Endangered based on the International Union for Conservation of Nature Red List Categories and Criteria B2a.     

A new species of Lichtheimia (Mucoromycotina,Mucorales) isolated from Brazilian soil

During studies on Mucorales in semiarid and littoral dune areas in the northeast of Brazil, two cultures of an Absidia-like species were isolated from soil. They were characterized based on morphological, physiological and molecular data (5.8S and LSU rDNA sequences). The phylogenetic analyses of the isolates revealed that they belong to the Lichtheimiaceae and are closely related to species of Lichtheimia. The two isolates produced simple or branched, erect and circinate sporophores, occasionally with a septum under the sporangia, characteristics also common in Lichtheimia species. However, different from the described Lichtheimia species, the columellae of our isolates were mainly short hemispherical, never spatulate or elliptical and without projections. Sometimes, a long conical or bell shaped apophysis was found. Both isolates grew better at 30–35 °C, with no development at 42 °C, and giant cells were not observed. Based on the evidence of the analyzed datasets a new species of Lichtheimia is proposed.     

Two new species of Martensia (Delesseriaceae, Rhodophyta) from Jeju Island, Korea

Two new species of Martensia (Delesseriaceae, Rhodophyta) are described from Jeju Island, Korea. Martensia jejuensis is characterized by the thallus of long linear axes and a proximal membranous part (initial blade), the linear axes that are derived from the longitudinal lamellae of the latticework, the flabellate bladelets arising from the linear axes terminally and laterally, the leading margins of the latticework giving rise to spine‐like or spatulate projections at intervals, and tetrasporangia borne on the whole thallus except for the spatulate projections. Martensia bibarii is characterized by the fimbriate aspect, the ribbon‐like blade with lobes, the flabellate bladelets derived from the lobes of the blade, the bladelets bearing the fringe or the latticework distally, the fringe consisting of many fine and strap‐shaped lamellae, and tetrasporangia borne only on the blade.     

Sur quelques flores du Carbonifère des Pyrénées béarnaises

The fossil Carboniferous flora of various localitiesof the «zone primaire axiale in Pyrénées Mountains, which was mainly known only by lists of determinations, is described and figured for the first time, due to the recent discovery of a very nice fossiliferous locality. The plant association comprises Lepidophyta, Arthrophyta, Filicophyta, Pteridospermaphyta and Cordaitophyta, with the following dominant species: Neuralethopteris schelehanii (Stur), Karinopteris acuta (Brongniart), Eusphenopteris hollandica (Gothan & Jongmans), Paripteris gigantea (Sternberg), Calamites cf. cistiiformis (Stur) and Corynepteris sp.Such an association is typical for an Upper Namurian B-Lower Namurian C age in Western Europe. The biostratigraphic results are compared with the data obtained by Goniatites found also in these localities.The identity of such plant-assemblages from WesternEurope as well as South and North-East China is in favour of a continental continuity between these provinces during the Namurian.     

Une faune de Mollusques bivalves duNamurien des Pyrénées centrales francaises

New outcrops of Carboniferous sediments in the Zone axiale of the Central French Pyrénées yielded florae and faunae of Namurian age. Among this lot of fossils, the Molluscs Bivalvia are worth particular attention. They were collected from detritical layers, located near the Ardengost Limestone; the various lithological characteristics of these layers are briefly described. The palaeontological study allows to record 13 species; among them, 11 were previously mentioned from the Namurian but it is underlined here that the determination of species remains difficult. The clear predominance of the epifauna and the fineness of the sediments agree to suggest quiet environments. At last, this fauna corroborates the great rise, during the Upper Carboniferous, of the class Pteriomorpha amongst the Bivalvia.     

Leafy branches of Gangamopteris from the Gzhelian–Asselian of westernmost Gondwana

The first reconstructions of glossopterids interpreted this Gondwanan group as arborescent, deciduous plants, with leaves and reproductive structures inserted on short shoots, which were arranged on long branches. The leaves are its most abundant organ in the fossil record, but they are mainly found isolated. The arrangement of the leaves as terminal whorls or tight spirals has been the most accepted phyllotaxis hypothesis. The few examples of leaf impressions preserved in connection with axes correspond mainly to leaves of Glossopteris Brongniart, and mostly without clear evidence of the type of insertion. Several specimens of Gangamopteris McCoy leaves attached to axes from the Bajo de Véliz Formation (Latest Carboniferous–Earliest Cisuralian) facilitate reconstruction of the foliar arrangement of the genus, to date known mostly from isolated leaves. The available evidence from the new specimens confirms a variation from well-spaced to dense helical insertion of the leaves without forming true whorls, and discards the early notion that they were mainly clustered apically on short shoots in a similar manner to the extant Ginkgoales.     

New data on the distribution of the Upper Carboniferous (Pennsylvanian) flexible crinoid Cibolocrinus (Crinoidea,Flexibilia)

Two new species of flexible crinoids of the genus Cibolocrinus (Crinoidea, Flexibilia) from the Upper Carboniferous of the Moscow Region are described: C. kutasovi (Moscovian Stage, Podolskian Regional Substage) and C. gerassimovi (Gzhelian Stage, Dobryatinian Regional Substage). The first species, C. kutasovi, belongs to a group with low cone shaped cups that first appeared in the Moscow Basin and then spread to the Midcontinent of North America. In one specimen of C. gerassimovi the smallest infrabasal plate is situated in the A ray, which is not typical for flexible crinoids. A poorly preserved crown of Cibolocrinus sp. from the Upper Carboniferous (Gzhelian Stage) of the Darvaz Ridge (western Pamir, central Tajikistan) is also described. The described specimens of Cibolocrinus from the Moscow Region and the Darvaz Ridge are the first reliable specimens of this genus described from Europe and Asia.     

First record of the genus Gratia Thomas (Ephemeroptera,Baetidae) from China with the description of a new species

A new species of Baetidae, Gratia baibungensis sp. n., is described and illustrated based on nymphal stage collected from the southeastern Tibet (Xizang) and the genus is reported for the first time from China. This new species can be readily differentiated from its congeners by the absence of a protuberance on the posterior margin of the abdominal tergum X, glabrate simple submarginal setae on the labrum, and the posterior margin of sterna VI–IX having much longer spatulate setae.     

Photosynthesis of Grass Species Differing in Carbon Dioxide Fixation Pathways : VIII. Ultrastructural Characteristics of Panicum Species in the Laxa Group

Ultrastructural studies of leaves of seven Panicum species in or closely related to the Laxa group and classified as C₃, C₄ or C₃-C₄ intermediate were undertaken to examine features associated with C₃ and C₄ photosynthesis. The C₃ species Panicum rivulare Trin. had few organelles in bundle sheath cell profiles (2 chloroplasts, 1.1 mitochondria, and 0.3 peroxisomes per cell section) compared to an average of 10.6 chloroplasts, 17.7 mitochondria, and 3.2 peroxisomes per bundle sheath cell profile for three C₃-C₄ species, Panicum milioides Nees ex Trin., Panicum decipiens Nees ex Trin. and Panicum schenckii Hack. However, two other C₃ species, Panicum laxum Sw. and Panicum hylaeicum Mez, contained about 0.7, 0.5, and 0.3 as many chloroplasts, mitochondria, and peroxisomes, respectively, as in bundle sheath cell profiles of the C₃-C₄ species. Chloroplasts and mitochondria in bundle sheath cells were larger than those in mesophyll cells for the C₄ species Panicum prionitis Griseb. and the C₃-C₄ species, but in C₃ species the organelles were similar in size or were smaller in the bundle sheath cells. The C₃-C₄ species and P. laxum and P. hylaeicum exhibited an unusually close association of organelles in bundle sheath cells with mitochondria frequently surrounded in profile by chloroplasts. The high concentrations in bundle sheath cells of somewhat larger organelles than in mesophyll cells correlates with the reduced photorespiration of the C₃-C₄ species.     

Structural and Biochemical Analysis of the Sheath of Phormidium uncinatum

The sheath of the filamentous, gliding cyanobacterium Phormidium uncinatum was studied by using light and electron microscopy. In thin sections and freeze fractures the sheath was found to be composed of helically arranged carbohydrate fibrils, 4 to 7 nm in diameter, which showed a substantial degree of crystallinity. As in all other examined motile cyanobacteria, the arrangement of the sheath fibrils correlates with the motion of the filaments during gliding motility; i.e., the fibrils formed a right-handed helix in clockwise-rotating species and a left-handed helix in counterclockwise-rotating species and were radially arranged in nonrotating cyanobacteria. Since sheaths could only be found in old immotile cultures, the arrangement seems to depend on the process of formation and attachment of sheath fibrils to the cell surface rather than on shear forces created by the locomotion of the filaments. As the sheath in P. uncinatum directly contacts the cell surface via the previously identified surface fibril forming glycoprotein oscillin (E. Hoiczyk and W. Baumeister, Mol. Microbiol. 26:699–708, 1997), it seems reasonable that similar surface glycoproteins act as platforms for the assembly and attachment of the sheaths in cyanobacteria. In P. uncinatum the sheath makes up approximately 21% of the total dry weight of old cultures and consists only of neutral sugars. Staining reactions and X-ray diffraction analysis suggested that the fibrillar component is a homoglucan that is very similar but not identical to cellulose which is cross-linked by the other detected monosaccharides. Both the chemical composition and the rigid highly ordered structure clearly distinguish the sheaths from the slime secreted by the filaments during gliding motility.     

Abscission of leaf laminas - An unnoticed factor in tussock grass formation

Drop of leaves at structurally defined abscission zones is a typical feature of dicotyledonous angiosperms. It is rare in monocots including the grass family (Poaceae). Some grass species have an odd, yet poorly studied pattern of leaves disarticulating regularly between the leaf sheath and the leaf lamina. Using species of three distantly related genera, such disarticulation zones were anatomically studied for the first time to clarify the structural background of shedding. The abscission zones of the three species turned out strongly different from each other in position, spatial arrangement and cellular architecture of different tissues, which is described and illustrated in detail. Breakpoints of the lamina were consistently defined by a sharp delineation of parenchymatous against sclerenchymatous tissue, irrespective of how these tissue types were arranged, e.g., sclerenchyma on the top of the sheath (Danthoniastrum), at the base of the lamina (Macrochloa), or alternating longitudinally with parenchyma (Aristida). The tussock grasses Danthoniastrum and Macrochloa had the most complicated and elaborately structured abscission zones. The results suggest that precise and efficient shedding of leaf laminas is an important factor enabling grasses to form tussocks as implicitly addressed already in 1890 by the agrostologist E. Hackel. Tussocks are a habitually conspicuous and ecologically important growth form of grasses in arid and/or alpine vegetation zones across the world. Judging from our exemplary results it must be expected that even further structural and mechanic patterns of precise leaf blade abscission will be found in tussock grasses of other grass subfamilies, such as the panicoids, chloridoids or arundinoids.     

Palynological evidence of Early Carboniferous sedimentation in the Llanos Orientales Basin, Colombia

Early Carboniferous palynological assemblages from the SM-4 well located in the Llanos Orientales Basin constitute the only definitively geological evidence of Carboniferous strata in this Basin. Stratigraphically significant species include: Anapiculatisporites concinnus, Apiculiretusispora mutiseta, Grandispora spiculifera, Indotriradites dolianitii morphon, Spelaeotriletes pretiosus and Prolycospora rugulosa. The presence of scarce acritarchs indicates a shallow marine environment. A Tournaisian age, probably reaching the Viséan, is proposed for the interval 2010-2340 ft based on the presence of distinctive spore species with previous records in the Viséan and Tournaisian of Western Europe and Western Gondwana. This report increases the knowledge about the distribution and composition of the Early Carboniferous palynological assemblages in Northern Gondwana.