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Full-Text Articles in Life Sciences
Interesting, Provocative, And Enigmatic: Morphological Observations On Southeastern Quillworts (Isoetes Isoetaceae, Lycopodiophyta, Rebecca D. Bray, Peter W. Schafran, Lytton J. Musselman
Interesting, Provocative, And Enigmatic: Morphological Observations On Southeastern Quillworts (Isoetes Isoetaceae, Lycopodiophyta, Rebecca D. Bray, Peter W. Schafran, Lytton J. Musselman
Biological Sciences Faculty Publications
The unique morphology of quillworts has received limited attention, and such studies have been limited to only a few species. Our extensive field work during the past two decades has revealed variation in the structures of the plant, including the rhizomorph, scales, phyllopodia, and abscission caps. Polarity of the axes of southeastern quillwort rhizomorphs varies from discoid (most species), to elongate, to upright with axis branching in several species. In species of intermittent streams, these branched rhizomorphs produce plantlets that break off in running water. Scales are tiny brown or black structures in alternating whorls with sporophylls (leaves). They are …
Isoetes Mississippiensis: A New Quillwort From Mississippi, Usa, Peter W. Schafran, Steven W. Leonard, Rebecca D. Bray, W. Carl Taylor, Lytton John Musselman
Isoetes Mississippiensis: A New Quillwort From Mississippi, Usa, Peter W. Schafran, Steven W. Leonard, Rebecca D. Bray, W. Carl Taylor, Lytton John Musselman
Biological Sciences Faculty Publications
Isoetes mississippiensis S.W. Leonard, W.C. Taylor, L.J. Musselman and R.D. Bray (Isoetaceae, Lycopodiophyta) is a new species known from two sites along tributaries of the Pearl River in southern Mississippi. This species is distinguished from other species in the southeastern United States by a combination of character states including a basic diploid (2n=22) chromosome count, laevigate megaspores, and a narrow velum covering less than one-third of the adaxial sporangium wall.
A New Species Of Diploid Quillwort (Isoetes, Isoetaceae, Lycophyta) From Lebanon, Jay F. Bolin, Rebecca D. Bray, Lytton John Musselman
A New Species Of Diploid Quillwort (Isoetes, Isoetaceae, Lycophyta) From Lebanon, Jay F. Bolin, Rebecca D. Bray, Lytton John Musselman
Biological Sciences Faculty Publications
A new species, Isoetes libanotica Musselman, Bolin & B. D. Bray (Isoetaceae, Lycophyta), is described from Akkar District of northern Lebanon. It is a seasonal terrestrial species of basaltic soils, diploid (2n = 22), with complete velum coverage. Megaspore diameter ranges from 338 to 477 mu m with remote, low tuberculate ornamentation and a low to obsolete equatorial girdle; microspore length ranges from 25 to 30 mu m, with echinate ornamentation. At the type locality of I. libanotica, two other Isoetes L. species occur sympatrically. These superficially similar Isoetes species can be differentiated from I. libanotica using megaspore …
Microspore Wall Morphogenesis And Orbicule Ultrastructure Of Isoetes, Khalid Alarid
Microspore Wall Morphogenesis And Orbicule Ultrastructure Of Isoetes, Khalid Alarid
Biological Sciences Theses & Dissertations
The microspore wall morphogenesis and orbicule ultrastructure of Isoetes were studied using electron microscopy. Microspore wall morphogenesis in five species of Isoetes (I. appalachiana, I. engelmannii, I. hyemalis, I. piedmontana, and an undescribed species from York Co., VA, USA) was studied using scanning and transmission electron microscopy. Results show that they generally have the same developmental stages in terms of microspore wall morphogenesis. The mature microspore wall consisted of four layers: perispore, paraexospore, exospore and endospore. Paraexospore formation began during the tetrad stage. The exospore was then formed between the paraexospore and the plasma membrane. During the free spore …
Isoetes Mattaponica (Isoetaceae), A New Diploid Quillwort From Freshwater Tidal Marshes Of Virginia, Lytton John Musselman, W. Carl Taylor, Rebecca D. Bray
Isoetes Mattaponica (Isoetaceae), A New Diploid Quillwort From Freshwater Tidal Marshes Of Virginia, Lytton John Musselman, W. Carl Taylor, Rebecca D. Bray
Biological Sciences Faculty Publications
Isoetes mattaponica is a rare quillwort of freshwater tidal rivers of eastern Virginia with a somatic chromosome number of 2n = 22. Megaspores have low rugulate muri on both the proximal and distal surfaces; the girdle is broad. Microspores are echinate-spinose with ornamented spines. Isoetes mattaponica may be one of the parents of several polyploids in the Southeastern United States.