A contribution to the embryology of Desmodium motorium (Houtt.) Merr. (= D. gyrans (L.f.) DC.) (Fabaceae)

Abstract

The anthers are tetrasporangiate. The anther wall comprises epidermis, fibrous endothecium, middle layer and tapetal layer. The tapetum is of the Glandular type and its cells remain uninucleate. Meiosis in pollen mother cells is normal and simultaneous cytokinesis leads to the formation of tetrahedral and decussate microspore tetrads. The pollen grains are shed at 2-celled stage. The ovule is campylotropous, bitegmic and crassinucellate. Meiosis in megaspore mother cell results in the formation of linear or occasionally T-shaped megaspore tetrad. The chalazal megaspore develops into Monosporic Polygonum type of embryo sac. Endosperm development is of the Nuclear type.     

An annual study of airborne pollen in northern Mexico City

An investigation of airborne pollen in northern Mexico City was carried out for one year. A total of 24 taxa were identified and classified according to the growing form in pollen of trees, weeds and grasses. Pollen grains were recorded all year round with a peak in December. The trees group showed the highest quantity of pollen as well as taxa diversity, although its peak period was in the dry season. The weeds and grasses emitted a larger quantity of pollen in the rainy season. The dominant taxa wereAlnus, Casuarina, Compositae and Gramineae. As for their relation with meteorological parameters, we found that the increase of pollen concentration was related to high temperatures, low relative humidity and high wind speed, the latter causing an increase of airborne pollen with no dilution at all. The hours with the highest pollen concentration where from 16:00 to 18:00.     

An annual study of airborne pollen in northern Mexico City

An investigation of airborne pollen in northern Mexico City was carried out for one year. A total of 24 taxa were identified and classified according to the growing form in pollen of trees, weeds and grasses. Pollen grains were recorded all year round with a peak in December. The trees group showed the highest quantity of pollen as well as taxa diversity, although its peak period was in the dry season. The weeds and grasses emitted a larger quantity of pollen in the rainy season. The dominant taxa wereAlnus, Casuarina, Compositae and Gramineae. As for their relation with meteorological parameters, we found that the increase of pollen concentration was related to high temperatures, low relative humidity and high wind speed, the latter causing an increase of airborne pollen with no dilution at all. The hours with the highest pollen concentration where from 16:00 to 18:00.     

Pollen morphology of Justicia L. (Acanthaceae) from Thailand and its taxonomic value

The acetolysed pollen of 33 species of the genus Justicia in Thailand is investigated using both light and scanning electron microscopy. The pollen of the genus is characterised as being isopolar, bilaterally or radially symmetrical, with mostly prolate or prolate spheroidal shape. Based on characters with high factor loading in the cluster analysis and principal components analysis, the studied species are divided into two major groups; one with 3-colporate with six pseudocolpi and the other with 2-porate or 2–3-colporate with aperture areas. The pollen morphology of each group is described and illustrated. Pollen characters are useful for taxonomic delimitation and relationships among Thai species.     

A new genus, a new species, and a new record of the family Darcythompsoniidae Lang, 1936 (Gopepoda, Harpacticoida) from the Gulf of California, Mexico

A new genus and new species of the family Darcythompsoniidae Lang (1936), and a new record of Darcythompsonia fairliensis (T. Scott, 1899), from a coastal lagoon in the south-eastern Gulf of California (Mexico), are reported and fully described and illustrated. Pabellonia olganoguerae gen. no v., sp.nov. shares features with Darcythompsonia T. Scott, 1906, such as the presence of a dimorphic second endopodal segment of the male second swimming leg, and with Kristensenia Por, 1983, the lack of sexual dimorphism in the caudal rami, anal operculum and urosomites. Thus it is considered closely related to these genera, and to represent a third component of mis lineage. Some notes on the biogeography of Darcythompsonia T. Scott, 1906, are also presented.     

A phenetic investigation of Psophocarpus Neck.ex DC.(Leguminosae-Phaseoleae)

Morphological data were gathered from 126 herbarium specimens representing ten species of Psophocarpus. Specimens were scored for 29 vegetative, 46 inflorescence, 16 legume and six seed characters. The data were analysed using cluster analysis and ordination and the results used to produce an overall phenetic classification. The proposed classification includes a tenth species recently distinguished, but undescribed by Verdcourt. Keys are provided to the subgenera and sections, as well as the ten taxa recognized and the classification is discussed in relation to previous classifications of the genus.     

On the identity of Ulex gallii Planchon (Leguminosae)

On the basis of the study of the original material used by Planchon, the typification previously made by other authors is discussed, and an interpretation of the U. minor-galli group is presented. We conclude that the name U. galli must continue in use in its traditional sense, and, therefore, U. cantabricus Alvarez Martínez el al. must become a mere synonym. The new combinations U. breoganii (Castroviejo & Valdés-Bermejo) Castroviejo & Valdés-Bermejo, stat. nov. and U. minor subsp. gallii (Planchon) Castroviejo & Valdés-Bermejo, comb. nov. are proposed.     

A new genus and species of mite (Acari: Acaridae) from Mexico

Comerinia chuetolamina gen. & sp. nov. was collected from a cargo of dried Daphnia imported to Britain from Mexico. Females can be distinguished from all others described in the family Acaridae in that setae 14, 15 and d5 are flattened dorsoventrally over most of the basal half. This region appears blade-like, bearing numerous strong pectinations along the ventral side. Males may be recognized by a series of characters, some of which reflect a close relationship with Forcellinia Ouds., 1924 and others with Tyrophagus Ouds., 1924. The position of the new genus in a commonly used key to adults of the family Acaridae is indicated.     

Distribution of quinolizidine alkaloid types in nine Ormosia species (Leguminosae-Papilionoideae)

Quinolizidine alkaloids were surveyed in 22 plant samples, representing nineOrmosia species and up to five different plant parts per species, using combined gas chromatography and mass spectroscopy. The detected alkaloids were classified into 40 structural types. There was a remarkable degree of dissimilarity of alkaloid-type profiles between any two plant samples, including those obtained from the same species and even from a single tree. The similarity of alkaloid-type profiles among the studied samples varied between 0% and 79% (Jaccard similarity coefficient). Of chemotaxonomic interest was the finding of acosmine inO. isthmensis, which previously had been reported only from the related genusAcosmium. Furthermore, the alkaloid-type profile ofO. panamensis seeds was distinct from that of all other samples, supporting the hypothesis that this species is only distantly related to the other Latin AmericanOrmosia species.     

Ruellia section Chiropterophila (Acanthaceae): a novelty from Mexico

RAMAMOORTHY, T. P., 1991. Ruellia section Chiropterophila (Acanthaceae): a novelty from Mexico. A brief review of the structure of the genus Ruellia is provided. A new section, ft. section Chiropterophila is described. Ideas regarding evolution in the section are offered. It is suggested that some of the taxa in the section may be neoendemics.     

Primary identifications and palynological observations of Perilla in China

Unresolved controversies concerning the classification of the monotypic genus Perilla L.have hindered the complete understanding and subsequent sustainable use of these vital food,oil,and medicinal plants to their full potential.In the present study,we used scanning electron microscopy to obtain palynological evidence from 21 samples of Perilla plants from seven provinces in China as a potential further attribute for classification.The findings showed that pollen grains from plants of 11 samples were oblate...     

Spinalona anophtalma, n. gen. n. sp. (Anomopoda, Chydoridae) a blind epigean cladoceran from the Neovolcanic Province of Mexico

Spinalona anophtalma n. gen. n. sp. is describedon parthenogenetic and ephippial females andmales from material collected in a temporary lagoonlocated in the Neovolcanic Province from Mexico at analtitude of 2507 m above sea level. It ischaracterized by a strong armature of the antenna,postabdomen and postabdominal claw, no compound eyeor ocellus, the exopod of thoracic limb IIIwith only four setae and that of P5 with only three setae.This new taxon has no relationwith blind Alona from hypogean habitats.     

A morphological and molecular assessment of the genus Sinotubimorpha (Halymeniaceae, Rhodophyta)

A critical reassessment of the morphological features of two closely related red algal genera,Grateloupia C.Agardh and Sinotubimorpha W.X.Li & Z.F.Ding (Halymeniaceae),pointed out that members of the t...     

旋扭山绿豆（Desmodiumintortum）凝集素的纯化与特性

旋扭山绿豆（Ｄｅｓｍｏｄｉｕｍｉｎｔｏｒｔｕｍ）凝集素的纯化与特性彭建宗,程双奇,陈兆平,莫熙穆（华南师范大学生物系,广州５１０６３１）关键词凝集素;旋扭山绿豆;亲和层析;糖蛋白豆科植物和根瘤菌之间的共生结瘤固氮关系早有报道。例如大豆只被Ｂ．仰。６。...