Topic
Sicyos
About: Sicyos is a research topic. Over the lifetime, 31 publications have been published within this topic receiving 186 citations.
Papers
TL;DR: The New-World Cucurbitaceae badly need a thorough taxonomic revision along 'Flora Neotropica' lines, and the present paper is hardly more than a stop-gap pending the undertaking of such an account, but may be found of value to workers on the crop plants in the family as indicating the taxa most closely allied to the cultivated species.
Abstract: Summary. The generic taxonomy of the tribes Melothrieae and Sicyoeae is clarified. The generic status of Doyerea and the generic distinctness of Gurania and Psiguria are confirmed. Dieudonnaea is included in Gurania, Frantzia, Polakowskia and Ahzolia in Sechium and Anomalosicyos, Sicyocaulis and Skottsbergiliana in Sicyos. Sechium is divided into Sect. Sechium and the new Sect. Frantzia. Nineteen new combinations, ten new species and one new name are proposed. Lists of accepted taxa studied, and of determinations of numbered exsiccata studied, arranged under countries and collectors, are given. These notes fall into two parts, the first containing general taxonomic comments, new taxa and other taxonomic and nomenclatural changes, the second a list of accepted taxa studied and exsiccata seen, arranged according to countries and collectors. The New-World Cucurbitaceae badly need a thorough taxonomic revision along 'Flora Neotropica' lines, and the present paper is hardly more than a stop-gap pending the undertaking of such an account. Nevertheless, it may be found of value, especially to workers on the crop plants in the family, as indicating the taxa most closely allied to the cultivated species and thus those most likely to be of use in broadening the genetic bases of the crops, and to curators of herbaria, in which numerous specimens are at present undetermined or misidentified. To the many collectors and others who have provided or loaned specimens for study, my gratitude for their indispensable kindness is freely given. Specimens of the new species (other than types) will be given in full in the forthcoming Flora of Venezuela account.
61 citations
TL;DR: Aim to infer the most plausible explanations for the presence of 14 species of the Neotropical cucurbit genus Sicyos on the Hawaiian Islands, two on the Galápagos Islands, three in Australia, and one in New Zealand.
Abstract: Aim To infer the most plausible explanations for the presence of 14 species of the Neotropical cucurbit genus Sicyos on the Hawaiian Islands, two on the Galapagos Islands, two in Australia, and one in New Zealand.
Location Neotropics, the Hawaiian and Galapagos archipelagos, Australia and New Zealand.
Methods We tested long-problematic generic boundaries in the tribe Sicyoeae and reconstructed the history of Sicyos using plastid and nuclear DNA sequences from 87 species (many with multiple accessions) representing the group’s generic and geographic diversity. Maximum likelihood and Bayesian approaches were used to infer relationships, divergence times, biogeographic history and ancestral traits.
Results Thirteen smaller genera, including Sechium, are embedded in Sicyos, which when re-circumscribed as a monophyletic group comprises 75 species. The 14 Hawaiian species of Sicyos descended from a single ancestor that arrived c. 3 million years ago (Ma), Galapagos was reached twice at c. 4.5 and 1 Ma, the species in Australia descended from a Neotropical ancestor (c. 2 Ma), and New Zealand was reached from Australia. Time since arrival thus does not correlate with Sicyos species numbers on the two archipelagos.
Main conclusions A plausible mechanism for the four trans-Pacific dispersal events is adherence to birds of the tiny hard fruit with retrorsely barbed spines found in those lineages that underwent long-distance migrations. The Hawaiian clade has lost these spines, resulting in a lower dispersal ability compared with the Galapagos and Australian lineages, and perhaps favouring allopatric speciation.
29 citations
Journal Article•
TL;DR: The species was identified using the collected specimens and Flora Palaestina and the distribution of the species was given.
Abstract: Cirsium candelabrum Griseb. is reported for the first time from Thrace (Turkey). A description, including 2 photographs of the plant, and a map of its distribution in Turkey are presented.
25 citations
TL;DR: It is suggested that germination in these scarified seeds may have been prevented by resistance of inner membrane and fruit-seed coat to embryo expansion, and the MC when seeds became impermeable is in the range of that reported for seeds of species in five other families with PY.
Abstract: Sicyos is the only member of the Cucurbitaceae known to have water-impermeable seeds, that is, physical dormancy (PY), and development of seeds with PY has not been studied in detail in this family. Our primary aim was to describe seed development in Sicyos angulatus from pollination to seed maturity and to compare it with the development of water-impermeable seeds in other families reported in the literature. Full seed stage (highest moisture content [MC]) occurred 4–6 days after pollination (DAP) and physiological maturity occurred 20 DAP. Seeds became water impermeable 32 DAP, with 14.6% MC. The hilum was the site of water loss during the final stage of maturation drying. Excised embryos could germinate from 20 DAP to 36 DAP, whereas no intact seeds germinated during any stage of seed development. Mechanical scarification did not promote germination of seeds after the seed coat became water impermeable at 32–36 DAP. Based on a previous study of seed dormancy and germination in S. angulatus, we suggest that germination in these scarified seeds may have been prevented by resistance of inner membrane and fruit-seed coat to embryo expansion. The MC when seeds became impermeable (14.6%) is in the range of that reported for seeds of species in five other families with PY. Information on seed development in S. angulatus will be useful in planning the timing of management strategies for this pernicious annual weed.
22 citations
1 Dec 2011
TL;DR: Pollen grains of seven genera and 11 taxa of Cucurbitaceae, ocurring in the "Reserva do Parque Estadual das Fontes do Ipiranga", were studied.
Abstract: Pollen grains of seven genera and 11 taxa of Cucurbitaceae (Anisosperma passiflora (Vell.) A. Silva Manso, Cayaponia cabocla (Vell.) Mart., C. martiana (Cogn.) Cogn., C. pilosa (Vell.) Cogn., C. villosissima Cogn., Echinocystis racemosa (Steud.) Mart. Crov., Melothria campestre Naudin., M. cucumis Vell. var. cucumis, Sicydium gracile Cogn., Sicyos polyacanthos Cogn., and Wilbrandia verticillata (Vell.) Cogn, ocurring in the "Reserva do Parque Estadual das Fontes do Ipiranga", were studied. Descriptions and illustrations are presented for all studied species.
21 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 1 |
| 2019 | 1 |
| 2017 | 1 |
| 2013 | 2 |
| 2012 | 5 |
| 2011 | 3 |