Anatomy of the Dicotyledons.
About: This article is published in American Midland Naturalist.The article was published on 1950-11-01. It has received 2511 citations till now.
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TL;DR: It is shown for the first time that, even after prolonged submergence in water at substantial depth (>500 m), the wood structure may be well preserved and the botanical identification and the determination of the origin of the sunken wood were possible.
Abstract: Two trawl samples of natural sunken wood collected near Vanuatu were identified based on histological studies. Detailed descriptions were made and microphotographs of the cell types were taken, using the three classical sections (cross, tangential and radial). The botanical characters were compared first to the native flora of Vanuatu, then also to the introduced species. The possibility of transportation by ocean currents with a mainly southern and eastern direction is discussed. The first sample lacks apparent colonization marks. Its main histologic character is the presence of ‘paedomorphic type I rays’ which relates it to the shrubby genera Fitchia (Asteraceae) and Fuchsia (Onagraceae): both are known in Polynesia but they seem not to be recorded from Vanuatu. The second wood sample is densely colonized by molluscs and other fauna. It comes from a tree close to the Fabaceae-Mimosoideae, possibly belonging to the genera Leucaena or Serianthes, both known from Vanuatu. Our work shows for the first time that, even after prolonged submergence in water at substantial depth (>500 m), the wood structure may be well preserved. Therefore, the botanical identification and the determination of the origin of the sunken wood were possible. The two selected samples show completely different colonization patterns, which could be related to differences in chemical composition or to time elapsed since sinking.
63 citations
TL;DR: The microscopic anatomy of three galls located on Pistacia terebinthus leaflets, induced by three species of gallicolous aphids, is studied and hypertrophy and hyperplasia of parenchyma cells are observed.
63 citations
TL;DR: The creation of a comprehensive reference collection for French Guiana improves taxonomic resolution and has provided the necessary ground work for the interpretation of palaeoevironmental and archaeological records in the region.
62 citations
TL;DR: It seems that the plant may receive a nutritional benefit from the ants' presence by absorbing nutrients released from decaying nest material inside the stem, as well as increase the competitive fitness of the plants by removing encroaching vines.
Abstract: Three species of the genus Piper (P. cenocladum G.DG., P. fimbriulatum G.DG., P. sagittifolium G.DG.) from the wet evergreen forest of Costa Rica are associated with ants of the genus Pheidole in what appears to be a coevolved mutualistic relationship. The ants live in petiolar cavities and in the stems which they hollow out; the plant produces lipid-rich food bodies inside the petiolar cavities on which the ants feed. The ants appear to increase the competitive fitness of the plants by removing encroaching vines. More importantly, it seems that the plant may receive a nutritional benefit from the ants' presence by absorbing nutrients released from decaying nest material inside the stem. Ant-plant mutualisms involving several plant families have been described in the Old and New World tropics (Hocking, 1970; Janzen, 1967, 1969a, 1972, 1973a, 1975; Rehr et al., 1973; Whiffin, 1972). The swollen-thorn acacia and its obligate ant inhabitant, Pseudomyrmex, is the most thoroughly studied ant plant, or myrmecophyte (Janzen, 1967, 1969a, b). However, most of the ant-plant associations described in the New World tropics are facultative. It is often the case that the plant produces extrafloral nectaries and is associated with aggressive ants that feed on the nectar source and in turn presumably protect the plant from herbivory (Bequaert, 1922; Carroll, 1974; Whiffin, 1972). We describe a situation involving three species of plants of the genus Piper (P. cenocladum C. DC, P. fimbriulatum C. DC, P. sagittifolium C. DC) that are always associated with ants of the genus Pheidole in what appears to be a coevolved mutualistic relationship. The occurrence of ants in these Piper species has been previously noted (Burger, 1972), but there are no* descriptions of the benefits that both ants and plant derive from the relationship. Piper cenocladum and P. fimbriulatum are slender shrublike plants that grow commonly to a height of 4 m, although P. fimbriulatum sometimes reaches a height of 7-8 m. Both species live in the understory of the wet evergreen forest of Costa Rica between sea level and approximately 1100 m altitude. Piper cenocladum is endemic to Costa Rica and is found only on the Caribbean coast, while P. fimbriulatum is found only on the Pacific coast of Costa Rica and in western Panama (Burger, 1971). Piper sagittifolium is a smaller herbaceous plant seldom exceeding 1.5 m in height and has only been recorded from the 1 Present address : Department of Zoology, University of Michigan, Ann
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