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: Vessel density expressed by its distribution in latewood and porosity type showed that ring-porosity is common in individuals from high latitudes, and redundancy analysis revealed that the first pair of canonical variates are significant, thus the canonical variate, named distribution, represents a gradient of maximum temperature of the warmest period, annual temperature range, and latitude in its area of distribution.
Abstract: Buddleja cordata is an evergreen species of wide distribution in Mexico that is represented by shrubs and trees. Wood variability of B. cordata was evaluated in relation to plant size as well as latitude, altitude, soils, and climatic data. Canonical correlation analysis (CCA) showed that two canonical correlations are significant (Wilks' λ, p<0.0001) and explained 76% of total variance. Redundancy analysis revealed that the first pair of canonical variates are significant, thus the canonical variate, named distribution, represents a gradient of maximum temperature of the warmest period, annual temperature range, and latitude in its area of distribution; whereas the canonical variate named wood represents vessel density, fiber length, and plant size, best associated to the environmental gradient. Vessel density expressed by its distribution in latewood and porosity type showed that ring-porosity is common in individuals from high latitudes. Temperatures below zero or lack of rainfall during several months might induce porosity variability in B. cordata as suggested by CCA, but was not related to phenology since the species is evergreen along its latitudinal range. Plant size was also influenced by extreme temperature and rainfall. Shorter plants are distributed in the northern population or driest sites located in north-central Mexico, and in addition, fiber length followed an allometric relation with individuals' height. Wood characters in B. cordata as for simple perforation plate, helical thickenings, type of intervascular and vessel-ray pits, scanty paratracheal parenchyma, and heterogeneous type IIB rays were not correlated with plant size, climate, and soil parameters or species distribution. These features are common with other species of Buddleja.
33 citations
01 Jan 1994
TL;DR: Character analyses are extended to chromosomal, morphological, phytochemical, and ultrastructural features, augmenting floral morphological and palynological characters discussed earlier, to improve cladistic and phenetic studies of the Centrospermae.
Abstract: To improve cladistic and phenetic studies of the Centrospermae (Caryophyllales or Chenopodiales), character analyses are extended to chromosomal, morphological (vegetative), phytochemical, and ultrastructural features, augmenting floral morphological and palynological characters discussed earlier (Rodman 1990). A dataset of 76 characters was analyzed with the computer programs PAUP (phylogenetic analysis using parsimony; for cladistics) and NTSYS (numerical taxonomy system of computer programs; for phenetics), and the results are compared with previous findings and with recent macromolecular data. Stegnosperma is collateral to all remaining centrosperms, which constitute four major assemblages: Amaranthaceae-Chenopodiaceae; Caryophyllaceae-Molluginaceae; Nyctaginaceae and Phytolaccaceae s.s. with Agdestis and Rivinaceae; and the succulents Aizoaceae, Cactaceae, and Portulacaceae (including Basellaceae, Didiereaceae, and Hectorellaceae). Paraphyly afflicts all four groups, and several additional taxa remain problematic: Achatocarpaceae, Barbeuia, Halophytum, Lophiocarpus, and Microtea. New macromolecular data from restriction site analyses and nucleotide sequencing promise to invigorate discussion of centrosperm phylogeny but will create debate over morphological versus molecular approaches in plant systematics.
33 citations
TL;DR: This first large-scale study comparing leaf crystal macropatterns of the species-rich sister genera Piper and Peperomia focuses on identifying types of calcium oxalate crystals and their macrop atterns in leaves of both genera.
Abstract: Premise of the study: This is the first large-scale study comparing leaf crystal macropatterns of the species-rich sister genera Piper and Peperomia It focuses on identifying types of calcium oxalate crystals and their macropatterns in leaves of both genera The Piper results are placed in a phylogenetic context to show evolutionary patterns This information will expand knowledge about crystals and provide specific examples to help study their form and function One example is the first-time observation of Piper crystal sand tumbling in chlorenchyma vacuoles
Methods: Herbarium and fresh leaves were cleared of cytoplasmic content and examined with polarizing microscopy to identify types of crystals and their macropatterns Selected hydrated herbarium and fresh leaf punches were processed for scanning electron microscopy and x-ray elemental analysis Vibratome sections of living Piper and Peperomia leaves were observed for anatomical features and crystal movement
Key results: Both genera have different leaf anatomies Piper displays four crystal types in chlorenchyma-crystal sand, raphides, styloids, and druses, whereas Peperomia displays three types-druses, raphides, and prisms Because of different leaf anatomies and crystal types between the genera, macropatterns are completely different Crystal macropattern evolution in both is characterized by increasing complexity, and both may use their crystals for light gathering and reflection for efficient photosynthesis under low-intensity light environments
Conclusions: Both genera have different leaf anatomies, types of crystals and crystal macropatterns Based on Piper crystals associated with photosynthetic tissues and low-intensity light, further study of their function and association with surrounding chloroplasts is warranted, especially active crystal movement
33 citations
TL;DR: The results clearly indicate that thePodalyrieae andLiparieae are monophyletic and that they should be united, but that Hypocalyptus andCadia should be excluded.
Abstract: Taxonomic relationships amongst the genera of the southern African tribesPodalyrieae andLiparieae are discussed. Data gained from morphological, cytological and chemical investigations are analyzed cladistically to determine relationships. The genusCadia (tribeSophoreae) is included in the investigation to establish whether it should be transferred to thePodalyrieae. The results clearly indicate that thePodalyrieae andLiparieae are monophyletic and that they should be united, but thatHypocalyptus andCadia should be excluded. Within the monophyletic group, there are two distinct subclades each supported by three apomorphies. The results also show that there is a strong sister relationship betweenAmphithalea andCoelidium. In the taxonomic treatment theLiparieae are placed into synonymy under thePodalyrieae and two subtribes are recognized. A key to the genera in the tribe is given, followed by a synopsis of the genera.
33 citations
TL;DR: In this paper, a synchronous site-catchment study was made in the middle Rhone valley with the aim of obtaining a synthetic image of a particular cultural period the Mid Neolithic, “Chasseen”.
33 citations