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: A cladistic analysis based on 63 morphological characters was carried out on the tribe Colletieae including two presumed closely related genera, Geanothus and Noltea as outgroupS, finding the Colletia species from a well supported monophyletic group, while monophyly of the disjunct genus Discaria could not be confirmed.
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TL;DR: Piper regnellii has two types of trichomes: pearl glands and sac-like trichome, both of which reach maturity in the young leaves found in the shoot apex.
Abstract: Piper regnellii has two types of trichomes: pearl glands and sac-like trichomes. Both secretory trichomes originate from the protoderm of the leaf primordium and reach maturity in the young leaves found in the shoot apex. The pearl glands are more abundant on the abaxial surface, while the sac-like trichomes cover completely both young leaf blade. The density of both trichomes decreases during blade expansion, being scarce in the adult leaf. The pearl glands are composed of a basal cell and an apical cell whose shape ranges from semi-globular to spatula-like. Secretion release occurs after rupture of the distended cuticle. The sac-like trichomes are composed of a basal cell, 1-2 stalked cells and an apical conical cell parallel to the leaf surface. The secretion is accumulated in minute subcuticular spaces. No cuticular ruptures have been observed.
24 citations
TL;DR: In this article, an estudo de anatomia foliar by microscopy optica and microscopy eletronica de varredura in Mentha spicata X suaveolens, caracterizing histologicamente a lâmina foliar, is presented.
Abstract: O presente trabalho tem como objetivo realizar um estudo de anatomia foliar por meio de microscopia optica e de microscopia eletronica de varredura em Mentha spicata L. e Mentha spicata X suaveolens, caracterizando histologicamente a lâmina foliar. Seccoes transversais e paradermicas da regiao mediana do limbo foliar mostraram a presenca de epiderme unisseriada, coberta por uma fina camada de cuticula, apresentando tricomas glandulares do tipo capitado e peltado e nao glandulares unisseriados multicelulares, nao ramificados. O mesofilo de ambas as especies e dorsiventral, com parenquima palicadico uniestratificado, com celulas alongadas e rico em inclusoes citoplasmaticas. O parenquima lacunoso e formado por tres a quatro camadas de celulas irregulares. Os tricomas capitados presentes sao classificados como do tipo I, e apresentam-se com uma celula basal, uma celula peduncular e uma grande celula apical, cujo formato varia de circular a piriforme. Os tricomas peltados consistem de uma celula basal, uma celula peduncular curta, larga e unicelular, com paredes externas cutinizadas e uma cabeca grande multicelular com 12 celulas secretoras, distribuidas radialmente em dois circulos concentricos, o central com 4 celulas e o externo com 8 celulas, as quais acumulam o produto da secrecao em uma cavidade entre a cuticula e as celulas secretoras; o pe do tricoma glandular esta inserido em 11 celulas epidermicas. Ha predominância de tricomas capitados em relacao aos tricomas peltados em ambas as especies de Mentha.
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TL;DR: Investigations of the wood anatomy, foliar anatomy, floral anatomy, pollen morphology, chromosome cytology, morphology, and distribution of these plants were undertaken in an effort to determine their relationships.
Abstract: From the time of Linnaeus to 1937 more than 40 generic, specific, or form names have been proposed for plants of this relatively little known and geographically restricted polygonaceous genus. As treated here it includes nine species-eleven taxa since two species are further divided into two varieties each. Morphologically and anatomically plants of the genus are quite similar. They possess ocreae and the other distinguishing features of the family. Their flowers consist of two outer and three inner sepals; eight stamens in an outer series of five (two pairs and a single stamen) and an inner series of three (frequently with distinctive, dilated filaments) ; and a tricarpellate ovary which matures as an achene. The plants are mostly erect, 1-20 dm tall, and bear mostly erect branches which appear to be internodal because each branch is adnate to the stem which produces it for a considerable distance above the node at which the branch actually originates. This apparently internodal branching can be used to separate Polygonella from the remainder of the family. Within this pattern of basic similarity oceur differences in growth habit, duration, and sexuality. Some plants of the genus are annual, others perennial. The annuals are erect and subherbaceous with an evident main stem from which graceful, ascending, secondary branches arise. The perennials are in general, suffruticose, not so tall, but are leafier and more branched than the annuals. Different species in both groups produce perfect flowers or are dioecious. Several annual species are gynodioecious; one, gynomonoecious. The geographic range of the genus includes inland and coastal sands from southeastern Canada to the vicinity of Miami, Florida. Polygonella articulata occurs in Maine and in the Great Lakes lowlands as far west as Minnesota, down the Mississippi Valley into northern Missouri, and down the Atlantic coast to North Carolina, whereas P. americana ranges westward from Georgia to New Mexico and northward up the Mississippi Valley to southern Missouri. Four taxa are endemic to Florida, and four others occur there. P. parksii is endemic to Texas. The most nearly complete consideration of Polygonella can be found in Small (1933). Here the plants are placed in 13 species under 4 genera. Small himself described 5 of these species and 2 of the genera. In this study investigations of the wood anatomy, foliar anatomy, floral anatomy, pollen morphology, chromosome cytology, morphology, and distribution of these plants were undertaken in an effort to determine their relationships.
24 citations
TL;DR: In this paper, four types of thickenings are described: faint striations, light helical, prominent helical and very prominent close helical thinnings. But they were not observed in a further eighty-eight species.
Abstract: SUMMARY
Helical thickenings were observed on the vessel walls of ninety woods indigenous to New Zealand. They were not observed in a further eighty-eight species. Four types of thickenings are described: faint striations, light helical thickenings sometimes merging with the vessel wall, prominent helical thickenings and very prominent close helical thickenings. These types are illustrated with scanning electron micrographs.
Although the helical winding orientation was predominantly in the S-direction, considerable variation was observed in the helical winding angle both between adjacent vessel members of similar dimensions, and also within individual cells.
Vestures were observed adhering to the helical thickenings in three species.
24 citations