首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
New information on the fruit, inflorescence, flower, and pollen ofPhrygilanthus nudus Molina indicates that it belongs toPsittacanthus, leading to the new combinationPsittacanthus nudus (Molina) Kuijt & Feuer.  相似文献   

2.
3.
Leaf flavonoids were isolated and characterized from the seven taxa of Hypericum, formerly segregated as Ascyrum and Crookea. These included flavonol 3-glycosides based on quercetin and kaempferol and flavone-O-glycosides and C-glycosides based on apigenin and luteolin. The flavonoid data do not indicate that the taxe of Ascyrum and Crookea form a single coherent group and hence support their merger with Hypericum.  相似文献   

4.
The early anthropoid species initially described asAegyptopithecus zeuxis Simons, 1965, from the Oligocene of Egypt, although retained by many authors in the monotypic genusAegyptopithecus, has been lumped by others into the genusPropliopithecus. Similarly, the species originally described asParapithecus grangeri Simons, 1974, has been ranked by some authors in a monotypic genusSimonsius, while others retain it inParapithecus. Criteria to be considered in resolving these taxonomic debates are (1) the adequacy and consistency of proposed morphological differences between species; (2) analogy with the degree of morphological variation tolerated within extant genera; and (3) nomenclatural conservatism. A philosophy that would require strict monophyletic classification is of insufficient practical value for assessing the validity of Fayum genera. Characters cited as distinguishing vetweenAegyptopithecus andPropliopithecus, and betweenSimonsius andParapithecus, are reviewed and evaluated. The results indicate thatA. zeuxis is generically distinct from species ofPropliopithecus, based on differences in the crown structure and proportions of the molars.Pa. grangeri cannot be shown to differ at the generic level from the type and only known specimen ofPa. fraasi, thus establishing Simonsius as a junior synonym ofParapithecus.  相似文献   

5.
A reclassification of the tribe Sileneae compatible with molecular data is presented. The genus Eudianthe ( E. laeta and E. coeli-rosa ) is restored. Viscaria, Ixoca (= Heliosperma ), and Atocion together form a well supported monophyletic group distinct from Silene and Lychnis , and are recognized at generic level. With Agrostemma and Petrocoptis , the number of genera in the tribe sums up to eight. The new combinations Silene samojedora, Silene ajanensis, Lychnis abyssinica, Atocion asterias, Atocion compacta, Atocion lerchenfeldiana , and Atocion rupestris are made.  相似文献   

6.
A reclassification of the tribe Sileneae compatible with molecular data is presented. The genus Eudianthe ( E. laeta and E. coeli-ma) is restored. Viscaria, Heliosperma , and Atocion together form a well supported monophyletic group distinct from Silene and Lychnis , and are recognized at generic level. With Agrostemma and Petrocoptis , the number of genera in the tribe sums up to eight. The new combinations Silene samojedorum, Silene ajanensis, Lychnis abyssinica, Atocion asterias, Atocion compactum, Atocion lerchenfeldiana , and Atocion rupestre are made.  相似文献   

7.
Abstract. Despite the short maxillary stylets of its members, the Williamsiellina is interpreted as a highly derived, rather than as an ancestral, group of Phlaeothripidae. Four genera are placed in synonymy with Sophiothrips Hood (Nanothrips Faure; Zaxenothrips Crawford; Bagnalliola Priesner; Nanimothrips zur Strassen) as a result of studies on three new species. Two of these (aleurodisci and duvali) comprise a new species-group endemic to New Zealand; the third (greensladei) is found in Australia and New Zealand but is closely related to species from the Azores and Southern France,  相似文献   

8.
Job Kuijt 《Brittonia》1990,42(1):66-69
The combinationLigaria teretiflora (Rizzini) Kuijt is proposed, based onPsittacanthus teretiflorus Rizzini, adding a second species to the genus.Ligaria teretiflora differs fromL. cuneifolia (Ruiz & Pavón) Van Tieghem in having articulated pedicels and obovate leaves which lack a necrotic apex.  相似文献   

9.
The formerly obscure genusOryctina v.Tiegh. is redescribed and validated. It is shown to include two species, an old one, previously known asOryctanthus scabridus Eichl., nowOryctina scabrida (Eichl.) v.Tiegh., and a new one,Oryctina subaphylla Rizz., both from Brazil.  相似文献   

10.
11.
Fruits of the tree Nuytsia floribunda are dispersed by wind during autumn to mid-winter when conditions are suitable for germination. While the greatest density of fallen fruits occurs beneath the canopy, most are dispersed well beyond the tree in the direction of the prevailing west-southwesterly winds, with a minor peak corresponding to the easterlies. A multiple regression equation, which accounted for 77.5% of variance, was derived to account for the greatest dispersal distance per tree. This comprises, in decreasing order of importance, tree height, log (fruit load), and leeward and windward plant cover in the vertical plane. Extrapolation indicated a maximum distance of about 50 m can be expected, which is insufficient to account for the location of at least 6.5% of adult trees at the study site. This supports other evidence that suckering may play a major role in the spread of this species. Additional experiments confirmed the importance of wind velocity in the distance reached by fruits and the absence of biotic dispersal agents.  相似文献   

12.
Three natural flavonols compounds have been isolated from the ethyl acetate fraction of Scurrula ferruginea Danser (Loranthaceae). Besides quercetin and quercitrin, an unusual flavonol glycoside 4"-O-acetylquercitrin was isolated. Structures were determined using spectroscopic methods including UV, NMR and HRMS-EI. The incidence of 4"-O-acetylquercitrin, not previously reported in the Loranthaceae, is discussed. Cytotoxic evaluation on four human cancer cell lines showed quercetin to be the most active with IC50 of 35 microM on U251 (human glioblastoma cells).  相似文献   

13.
The family Oocystaceae (Chlorophyta) is a group of morphologically and ultrastructurally distinct green algae that constitute a well‐supported clade in the class Trebouxiophyceae. Despite the family's clear delimitation, which is based on specific cell wall features, only a few members of the Oocystaceae have been examined using data other than morphological. In previous studies of Trebouxiophyceae, after the establishment of molecular phylogeny, the taxonomic status of the family was called into question. The genus Oocystis proved to be paraphyletic and some species were excluded from Oocystaceae, while a few other species were newly redefined as members of this family. We investigated 54 strains assigned to the Oocystaceae using morphological, ultrastructural and molecular data (SSU rRNA and rbcL genes) to clarify the monophyly of and diversity within Oocystaceae. Oonephris obesa and Nephrocytium agardhianum clustered within the Chlorophyceae and thus are no longer members of the Oocystaceae. On the other hand, we transferred the coenobial Willea vilhelmii to the Oocystaceae. Our findings combined with those of previous studies resulted in the most robust definition of the family to date. The division of the family into three subfamilies and five morphological clades was suggested. Taxonomical adjustments in the genera Neglectella, Oocystidium, Oocystis, and Ooplanctella were established based on congruent molecular and morphological data. We expect further taxonomical changes in the genera Crucigeniella, Eremosphaera, Franceia, Lagerheimia, Oocystis, and Willea in the future.  相似文献   

14.
Loranthaceae (73 genera and ca. 900 species) comprise mostly aerial hemiparasitic plants. Three monotypic genera considered relicts are root parasites. The family is diverse in tropical areas, but representatives are also found in temperate habitats. Previous classifications were based on floral and inflorescence morphology, karyological information, and biogeography. The family has been divided into three tribes: Nuytsiae, Elytrantheae (subtribes Elytranthinae and Gaiadendrinae), and Lorantheae (subtribes Loranthinae and Psittacanthinae). Nuytsiae and Elytrantheae are characterized by a base chromosome number of x = 12, whereas subtribes Loranthinae (x = 9) and Psittacanthinae (x = 8) numbers are derived via aneuploid reduction. To elucidate the phylogeny of the family, we analyzed sequences from five genes (nuclear small and large subunit rDNA and the chloroplast genes rbcL, matK, and trnL-F) representing most genera using parsimony, likelihood, and Bayesian inference. The three root parasites, Nuytsia, Atkinsonia, and Gaiadendron, are supported as successive sister taxa to the remaining genera, resulting in a monophyletic group of aerial parasites. Three major clades are resolved each corresponding to a subtribe. However, two South American genera (Tristerix and Notanthera) and the New Zealand genus Tupeia, which were previously classified in subtribe Elytranthinae, are weakly supported as part of a clade representing the South American subtribe Psittacanthinae.  相似文献   

15.
16.
ONOFEGHARA  F. A. 《Annals of botany》1972,36(3):563-570
The growth response of Tapinanthus bangwensis (Engler and K.Krause) Danser to exogenous growth substances, indole-3yl-aceticacid (IAA), kinetin, and gibberellic acid (GA3), not only varieswith the concentrations of each of these substances in the mediumbut follows a similar trend in each case. Kinetin, IAA, andGA3 were found to enhance growth but not by very appreciableamounts, kinetin being the most effective growth promoter. Highconcentrations of these substances (5.0 and 10.0 ppm) exceptGA3 were toxic to the parasite. Gibberellic acid induced theproduction of accessory leaves at all the concentrations used.Kinetin was also effective in inducing accessory leaves butonly at a concentration of 1.0 ppm. Some of the lower concentrationsof the growth substances affected significantly some aspectsof the parasite's growth and development. Nevertheless, thegrowth in vitro was still slower than that in vivo.  相似文献   

17.
Anatomy of the endophyte of Viscum album L. (Loranthaceae). An anatomical investigation into the nature of the host-parasite interaction of V. album and several of its phanerogamic hosts using SEM and light microscopy was conducted. Three kinds of parasite cell (haustorial parenchyma cells, cells resembling transfer cells and haustorial tracheids) were identified at the host-parasite interface. The terms haustorial parenchyma and haustorial tracheid are defined. Haustorial tracheids were seen to have penetrated the walls of host vessel elements and it is suggested that V. album is able to establish on a wide range of hosts because of the anatomically plastic nature of its haustorium. The development of the haustorium depends to a large extent on the nature of the surrounding host tissues. Parasite-induced host abnormalities including hypertrophy, distorted xylem elements, vessel-wall penetration and tylosis-occluded vessels were observed. The macroanatomical features observed are discussed and interpreted by-proposing a new theory for the ontogenesis of the V. album haustorium. Cortical strands with 'chisel' and 'pencil' shaped apices were both found to be present at the same time on one plant and thus were not seasonally separated.  相似文献   

18.
Job Kuijt 《Brittonia》1994,46(1):72-74
A large-leaved, apparently dioecious species ofIxocactus,I. macrophyllus, is described from Brazil.  相似文献   

19.
The thickenings in the anther wall ofPhthirusa adunca are confined to the endothecium. This observation resembles the previous report onP. pyrifolia.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号