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1.
Ghamizi Mohamed; Bodon Marco; Boulal Mokhtar; Giusti Folco 《Journal of Molluscan Studies》1999,65(1):89-98
The new genus Atebbania is described for a new hydrobiid species,A.
bernasconii, which lives in groundwaters of southern Morocco.Of the Hydrobiidae genera
with known shell and anatomy Moitessieriais the closest to Atebbania. The
two share the following characters:shell elongate; teleoconch surface with evident
microsculpture;seminal receptacle absent. Atebbania is distinguished from Moitessieriaby: shell ovate; penis with a) apical stylet, b) one lobe bentdownward on left
(inner) side and c) penial duct running nearthe right (outer) side; posterior end of foot indented. Atebbaniabernasconii n. sp., lives in a limited area, the Tiznit plainin southern
Morocco. Other stygobiont hydrobiids from otherareas of Morocco are currently being studied.
None of them appearsto be closely related to A. bernasconii or to the species ofMoitessieria (Received 10 February 1998; accepted 30 April 1998) 相似文献
2.
Wild species in the genus A rachis L. have several desirablecharacters and are therefore of great interest for use in thegenetic improvement of A. hypogaea L. but only a few closelyrelated species have been used. There are many others whichcould not be used because they are incompatible with the cultivatedspecies. This paper reports techniques to produce hybrids fromincompatible crosses. 相似文献
3.
The classical and numerical taxonomy, palynology and the geographical distribution of the Genus Schizopepon are dealt with in the present paper. Having commented on various opinions regarding the systematic position of the genus, the present authors consider that C. Jeffrey’s treatment of Schizopepon as a new and monogeneric tribe, Schizopeponeae, should be supported.
The gross morphological characters in the genus are assessed from the taxonomic
point of view. Some characters, such as stamens with an elongated connective or not,
different insertions of ovules and various forms of ovaries and fruits, may be used for
distinguishing subgenera.
The pollen grains of all the species were observed under light microscope (LM) and
scanning electron microscope (SEM). The results show that a strong differentiation
has taken place in the pollen of the genus, and in consequence it may be regarded as an
important basis for dividing subgenera and species. Especially it should be pointed out
that degrees of development of colpi and positions of ora are positively correlated with
the external characters used for distinguishing subgenera.
According to the morphological and palynological characters, the genus Schizopepon
may be divided into three subgenera and eight species: 1. Subgenus Schizopepon: 5 species, S. bryoniaefolius Maxim., S. monoicus A. M. Lu et Z. Y. Zhang, S. dioicus Cogn.,
S. longipes Gagnep. and S. macranthus Hand.-Mazz.; 2. Subgenus Rhynchocarpos A. M.
Lu et Z. Y. Zhang: 1 species, S. bomiensis A. M. Lu et Z. Y. Zhang; 3. Subgenus Neoschizopepon A. M. Lu et Z. Y. Zhang: 2 species, S. bicirrhosus (C. B. Clarke) C. Jeffrey
and S. xizangensis A. M. Lu et Z. Y. Zhang.
The 8 OTU’s including all the species of this genus and 31 characters, of which 16 are morphological characters and 15 palynological characters, were used in the numerical taxonomic treatment. After standardization of characters, the correlation and distance matrices were computed. The correlation matrices are made to test the various clustering methods. At last, the UPGMA clustering method was selected and its result
is shown in the form of phenogram. The result of numerical analysis is similar to that of the classical classification.
Schizopepon Maxim. is a genus of East Asia-Himalayan distribution. China has all 8 species and 2 varieties, of which 6 species are endemic. Based on the statistics of spedies number, the distribution centre of the genus is considered to be in the Hengduan Mountains (Yangtze-Mekong-Salwin water divides) and the adjacent areas of the southwest China. 相似文献
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5.
An account is given of a hitherto undescribed species of Pityostrobusthe specimens of which come from the Lower Greensand of theIsle of Wight and for which the name Pityostrobus jacksoni issuggested. Structurally it has the general characters of thecones of the modern genus Pinus but no immediate affinity toan individual species of that genus is proposed. As a highlycharacteristic feature of the cone the seed-scale complexespossess much inflated apophyses, definite bract scales are alsopresent. The information obtained from sections through variousplanes is embodied in a reconstruction of one seed-scale complextogether with its bract scale. 相似文献
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8.
Infraspecific variation has been investigated in the marineepipelic diatom Hantzschia virgata using light and electronmicroscopy. Although the variation pattern in this species iscomplex and to some extent discontinuous, allowing the recognitionon phenetic grounds of four or five discrete infraspecific taxaincluding vars. virgata (= H. insolita), gracilis, leptocephala(= capitellata) and wittii (= intermedia), it is concluded thatto split the species would be imprudent. Variation has beenfound not only in characters such as valve outline and size,or stria density, but also in qualitative characterssuch as raphe, fibula and girdle structure, characters whichhave often been assumed to be constant within species, generaor taxa of higher rank: previous generalizations about the usefulnessof certain characters in distinguishing taxa of a given rankare seen to have been incautious. Hantzschia virgata (Roper) Grun., diatom taxonomy, infraspecific variation 相似文献
9.
斑龙芋属(天南星科)及近缘属植物的叶表皮形态 总被引:3,自引:0,他引:3
光镜、电镜下观察了天南星科天南星族下斑龙芋属2个种及近缘属13个种植物的叶表皮形态特征。实验结果显示,4属植物的叶表皮组成及其形态特征较相似,属间不存在明显差异,但某些特征在种间存在差异,可作为种的鉴别特征。叶表皮特征支持将单籽犁头尖和昆明犁头尖两个种合并为一个种。15个种的气孔器均具有2个副卫细胞,Stebbins andKhush认为这是气孔器类型中较具2个以上副卫细胞更进化的一种类型,而天南星科大多数族的气孔器都具有2个以上的副卫细胞,这也证明了天南星族是天南星科较进化的族。 相似文献
10.
Hwang Shu-mei 《植物分类学报:英文版》1993,31(2):105-126
Discussed in the present paper are evolutionary trends of important morphological characters of Deutzia, systematic position of several closely related genera, geographical distribution and characteristics of floristic elements. Finally the classificatory revison of the genus is made and a key to species is given. As a result, evolutionary trends of the important morphological characters in Deutzia are suggested; petals from imbricate to valvate, stamens from indefinite to definite, filaments from edentate to dentate, ovary from half-inferior to inferior. Therefore, the section Neodeutzia with valvate corolla and infinite stamens with edentate filaments should be included in this genus. The sections Neodeutzia and Mesodeutizia seem to be better considered as primitive taxa, while the section Deutzia advanced one. There are 52 species of Deutzia in China , which are grouped into two sections ( Sect. Mesodeutzia, Sect. Deutzia), four subsections (Subsect. Deutzia, Subsect. Grandiflorae, Subsect. Stenosepalae, Subsect. Cymosae)and 17 series.
Sixty- five species are so far recognised in the genus Deutzia. They are mainly distributed in E. Asia and disjunctively in N. America. China is therefore an area the richest in species of Deutzia in the world, making up 80% of the total species of this genus. The greatest concentration area is in Sichuan (23 species), Yunnan (21 species), Hubei (12 species) and Shanxi (10 species), this is boundary area between Sino-Himalayan subregion and Sino-Japanese subregion, where occur abundant species (including 39 endemic species) and diverse taxa (2 section and 4 subsection). Based on these facts it is proposed that the present center of distribution and differentiation of Deutzia be in the southern part of the Hengduan Mountains, the Qingling Range and C. China. 相似文献
11.
Pan Kai-Yu 《植物分类学报:英文版》1987,25(4):264-293
The genus Oreocharis as circumscribed here consists of 27 species including 5
varieties, of which 5 species and 4 varieties are described as new in the present paper. In the
work analysed were the external morphology and geographic distribution and examined under
SEM were pollen exine of 22 species and seed coat of 16 species. As a result, three types of the
corolla, two types of the anther, three types of the pollen exine and three types of the seed
coat are distinguished here in the paper. It is discovered that the corolla in the genus is relatively stable, though diverse, and highly correlated with the characters of pollen grains and
seeds. The corolla clearly bilabiate but constricted at the throat, occurring in O. auricula, O.
cordatula, O. aurantiaca, etc., for an example, is correlated with smooth, reticulate pollen exine
and partial tectum and the reticulate and smooth seed coat. For this reason the subdivision of
the genus in the paper is mainly based on the characters of the corolla, but combined with those
of the anther, pollen and seed coat. The genus is divided into four sections in the present classification. Dasydesmus Craib, based on a single species. O. bodinieri, is reduced here, and the
reasons are given. The genus is distributed mainly in the subtropics, and less frequently in the
tropics, of China south of 32.5°N and east of 98.5°E, with only two species beyond the border,
O. hirsuta in Thailand (only a single locality in Chiengmai) and O. aurea also found in north
Vietnam (see Fig. 1, Table 3).
Sect. 1. Stomactin (Clarke) Fritsch. Corolla urceolate-tubular, constricted at the throat,
with limb distinctly bilabiate; anthers broad-oblong; seed coat reticulate, smooth, rarely minutely tuberculate; pollen exine fine-reticulate, tectum partial and smooth, luminae slightly unequal in size.
Sect. 2. Orthanthera K. Y. Pan Corolla campanulate or campanulate-tubular; anthers broad-oblong; seed coat reticulate, muri smooth, rarely spiny-processed; pollen exine fine-reticulate,
with partial and smooth tectum and luminae slightly unequal in size, rarely exine insular and
fine-tuberculate, tectum perforate.
Setc. 3. Oreocharis Corolla thin-tubular; anthers broad-oblong; seed coat densely spinyprocessed, rarely fine-tuberculate; pollen exine insular, densely spiny-processed, rarely finereticulate and smooth, luminae unequal in size.
Sect. 4. Platyanthera K. Y. Pan Corolla campanulate; anthers hippocrepiform; seed coat
densely spiny-processed; pollen exine fine-reticulate, tectum perforate, luminae small, nearly
equal in size.
In the section Stomactin, although the constriction of corolla at its throat is a specialized
character, the characters of seed coat, pollen grains and anthers are apparently primitive. Therefore it may be said at least that more primitive characters are preserved in the section. In the
section Oreocharis, on the contrary, the characters of corolla, seed coat and pollen exine are all
advanced. And in the section Platyanthera, the seed coat, pollen (with perforate tectum) and
anthers have developed rather specialized characters. 相似文献
12.
A population of Pseudotachea litturata (Pfeiffer, 1851) fromTarifa (Càdiz, Spain) has been studied. The morphologicalresults are compared with those from P. splendida, Iberus gualtierianus,I. alonensis, I. marmoralus, I. guiraoanus and four speciesof the genus Cepaea using, as an exploratory method, the Wagnerparsimony procedure and 18 characters of the shell, genitalsystem and karyotype have been analysed. According to this methodit seems that the taxonomical position of P. litturata in thegenus Pseudotachea is confirmed, and agrees with the phylogeneticalrelationships in this group of species. The genus Cepaea seemsto be well established, although two species groups can be distinguished:C. nemoralisC. hortensis and C. syluaticaC. vindobonensis.These differ mainly in chromosome number, diverticulum lengthand degree of shell polymorphism. Although the present resultsdo not allow us to clarify the current taxonomical problemswithin the genus Iberus, the species studied seem to belongto a natural group (Received 15 September 1987; accepted 1 January 1988) 相似文献
13.
五味子属种子形态及其分类学意义 总被引:5,自引:1,他引:4
用光学显微镜及扫描电镜对五味子属(Schisandra)10种96号样品的种子宏观形态和种皮的微观形态特征进行观察,首次对该属的种皮微观形态特征进行系统报道,并编排有分种检索表。研究结果表明:该属的种子宏观形态呈现平滑、细皱纹或瘤状突起,并认为五味子属种子形态可有从平滑到有细皱纹再到有瘤状突起的演化趋势;该属种皮表面微观形态可分为疣状突起型和网纹型。结合其它性状,本文认为网纹型所代表的两种植物应与本属中其它植物建立并列的分类单元。五味子属植物在种子形态特征上存在一定的差异,可为属以下、种以上的分类提供依据,并为探讨该属的系统演化提供有价值的参考资料。 相似文献
14.
Zafar A. Handoo 《Journal of nematology》2000,32(1):20-34
An identification key to 111 species of Tylenchorhynchus is given. Tylenchorhynchus is defined as containing only those species with four incisures in the lateral field. A compendium providing the most important diagnostic characters for use in identification of species is included as a supplement to the key. Some species in a related but unnecessary genus were placed in the genus Tylenchorhynchus, based on morphological structures and logical groupings of the species. Bitylenchus iphilus is transferred to Tylenchorhynchus. The diagnosis of Tylenchorhynchus is emended, and a list of all the valid species of the genus is given. The characters most useful for separating species are the stylet length, shape of lip region, number of lip annules, shape of tail and tail terminus, number of tail annules, and position of vulva (V%). As defined in the paper, the genus currently is composed of 111 valid species. 相似文献
15.
The Diatom Genus Tabellaria: I. Taxonomy and Morphology 总被引:1,自引:0,他引:1
A morphological study of natural populations of Tabellaria infresh water suggested that there were two fundamentally differenttypes of growth (and therefore frustule structure) in the genus,and this has been confirmed by means of unialgal clone cultures.The existence of these different types of growth forms the basisfor a revision of the genus. A diagnosis of T. quadriseptatanov. spec, is given, the specific limits of T. fenestrata andT. flocculosa are redefined, and the occurrence of T. binalisin Britain is reported for the first time. 相似文献
16.
A new genus and species of Planorbidae, Kessneria papillosa
n.gen.and sp. from the Northern Territory, Australia, are
described.The new genus is morphologically most similar to
Leichhardtia,another genus restricted to Northern Australia, from
which itdiffers in a number of important shell and anatomical
characters.The shell of the new genus differs from all other
planorbidsin having a raised, papillate protoconch, and is also
uniqueamongst Australian high-spired genera in being umbilicate and
inhaving a sinuate outer lip. (Received 12 May 2000; accepted 25 September 2000) 相似文献
17.
A new species of Oithona predominating in the neritic watersof Australia is described. This species resembles three otherspecies of the genus, but has several unique characters in thefamily Oithonidae. The morphological and geographical relationshipsof this species with allied species are discussed. 相似文献
18.
Two new species of prayine siphonophore are described from specimenscollected by the submersibles Johnson-Sea-Link I and II. Althoughthey possess some unique morphological features, the generalcharacters of these new species suggest that they belong tothe genus, Rosacea sensu Bigelow. These characters are discussedin relation to the detailed comparisons of other prayine speciesmade previously by Pugh and Harbison. 相似文献
19.
中国鹅膏菌属(担子菌)的物种多样性 总被引:12,自引:3,他引:9
鹅膏菌属(Amanita)是一个近世界性广布的大属,全球已被描述而又被承认的有近500种。在文献中,我国此属已记载约200种。然而,许多种都是原初描述于欧洲或北美的种类。近来的研究表明,东亚的鹅膏菌独特且有其自身的分布范围。东亚的有些种虽与产于欧洲或北美的某些种相似,但仔细的野外观察,详尽的形态解剖学和分子进化生物学研究结果表明,东亚的鹅膏菌是独立的分类群。在欧洲,人们有采集著名食菌恺撒鹅膏菌的习 相似文献
20.
Gametogenesis in the Genus Hydra 总被引:3,自引:0,他引:3
This paper comments on the induction of gametogenesis, on microscopicaland electronmicroscopical aspects of spermatogenesis and oogenesisand on fertilization in the genus Hydra. Spermiogenesis doesnot present any peculiarities. The ripe sperm contains no detectableacrosoinc. Egg-formation involves phagocytosis of entire oogoniaby growing oocytes. Several oocytes merge to a single oocyte,in which one nucleus becomes the germinal vesicle. The egg shellis formed only when the egg is fertilized. Various factors suchas the synchronization of gametogenesis, the length of sexualperiods, continuous release of sperm and the long life spanof sperm are considered to guarantee the fertilization of theeggs. 相似文献