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: The results suggest that evolution of lianescence can carry a high degree of specialization and developmental burden that might limit evolution back to self-supporting growth forms, under certain geographic and ecological conditions.
Abstract: Lianas are common in the Apocynaceae s.l. and are predominant in the subfamily Secamonoideae. Shrub-like taxa are rare within this subfamily but occur in Malagasy genera such as Secamone, Secamonopsis, and Pervillaea. We explored the evolutionary appearance of shrub-like growth forms in Malagasy Secamonoideae through a molecular phylogeny using chloroplastic sequences. The phylogeny revealed several independent appearances of shrub-like growth forms within the Secamonoideae. Biomechanics and development of the shrub-like growth form were detailed in one species, Secamone sparsiflora, which has upright and self-supporting young stems that become procumbent in older stages of development. Biomechanical investigations revealed characteristics atypical of both lianas and self-supporting shrubs. Anatomical development in S. sparsiflora is initially similar to lianas in the same clade but shows potentially neotenic retention of juvenile wood development for most of the growth trajectory. The results suggest that evolution of lianescence can carry a high degree of specialization and developmental burden that might limit evolution back to self-supporting growth forms. Under certain geographic and ecological conditions, such as geographic isolation, xeric conditions and/or reduced biotic competition, escapes from lianescence to other growth forms can occur in some angiosperm groups via relatively simple heterochronic shifts of mechanically significant growth processes.
58 citations
TL;DR: This review presents the botany, chemistry, traditional uses and pharmacological data of genus Kalanchoe and reports the isolation of polysaccharides, flavonoids, sterols, ascorbic acid, trace elements, organic acids, hydrocarbons, triterpenoids, phenolic components and bufadenolides.
Abstract: Genus Kalanchoe comprises hundred species. Different extracts of these Kalanchoe species have been widely used in traditional medicine. Recently it has been reported that Kalanchoe extracts possess various biological activities viz. antiviral, sedative, antiulcer, immunomodulatory, antileishmanial, CNS depressant, anti-inflammatory, thyroid peroxidase inhibitor, cytotoxic, hepatoprotective, antioxidant, analgesic, anticonvulsant, antimicrobial, inhibition of B cell development, cardiovascular, antihyperglycemic, acetylcholinesterase inhibition, insecticidal and larvicidal activities. Earlier studies on different Kalanchoe species have reported the isolation of polysaccharides, flavonoids, sterols, ascorbic acid, trace elements, organic acids, hydrocarbons, triterpenoids, phenolic components and bufadenolides. This review presents the botany, chemistry, traditional uses and pharmacological data of genus Kalanchoe.
58 citations
Cites background from "Anatomy of the Dicotyledons."
...The root is described as having red root tips, colored by an anthocyan pigment which is intensified by bright light [7,17]....
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...Xylem nearly always in the form of a continuous cylinder, only rarely dissected by wide rays [7,17]....
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...Crystals common, solitary, clustered, or in the form of sphaerites and crystal sand [7,17]....
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58 citations
TL;DR: ES raise important questions about the relationships between adaptation, morphogenesis, and phylogeny, and in particular, a great deal remains to be learned about the adaptive significance of ES, particularly inflorescences.
Abstract: Epiphylly is the occurrence of structures (leaves, shoots, inflorescences, etc.) on leaves. Although its occurrence was recognized without comment early in the history of descriptive botany, with the development of the classical shoot theory it became necessary to explain the deviation of leaves bearing epiphyllous structures (ES) from the positional criteria of this theory. Epiphyllous inflorescences have been interpreted primarily as resulting from the intervention of fusion, in order to retrieve the structures and positional relationships required by the classical theory. Epiphyllous buds, branches, leaves, etc. were regarded principally as accidental deviations from the accustomed positional relationships. There seems, however, to be some validity to the minority opinion of some earlier workers who rejected rigid application of the positional criteria of the classical shoot theory (and its consequent ad hoc explanations) to situations like epiphylly. Naturally occurring ES in the flowering plants are reviewed, as well as some of the results and implications of studies of the ontogeny of these structures. Finally, the significance of epiphylly is discussed with respect to our understanding of the shoot of Angiosperms, and the occurrence of intermediate structures. It seems best to dispense with the position criteria of the classical shoot model, and to accept leaves bearing ES as such, without further interpretation. This can be done in the context of newer models of the shoot which lack rigid criteria of position and which accept intermediate structures (such as leaves bearing ES) as such. In addition, ES raise important questions about the relationships between adaptation, morphogenesis, and phylogeny. In particular, a great deal remains to be learned about the adaptive significance of ES, particularly inflorescences.
58 citations
TL;DR: The literature on terminology of stomata and stomatal development is reviewed and the terminology rationalized and the classification of developmental types and of the developing cells should not be combined with the morphological classification of mature stomatic complexes.
58 citations