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The fossils, from the species  Umaltolepis mongoliensis,  date back to the early Cretaceous Period (some 100-125 million years ago). Scientists discovered the fossils in ancient peat deposits at the Tevshiin Govi mine in the steppes of central Mongolia. Results of the research, supported by the National Science Foundation (NSF), are published in this week's issue of the journal  Proceedings of the National Academy of Sciences (PNAS). "The stems and leaves are similar to the ginkgo tree, but the seeds, and especially the structures they are born in, are unlike any other known plant, living or extinct," says scientist Patrick Herendeen of the Chicago Botanic Garden, co-author of the  PNAS  paper. "Finding something like this does not happen very often." Scientists had previously uncovered fossils of  U. mongoliensis,  but those were in poor condition, making them difficult to study. Hundreds of better-preserved new fossils show that features of the ste...

A cross section one micrometer thick of a California scrub oak (Quercus agrifolia) leaf. Plantbiologists use images like these to 'lift the hood' of the leaf to identify and measure cells and tissues, labeled in this image. The waxy coatingon the outside of the leaf is called the upper and lower cuticle (UC and LC, respectively); beneath the cuticle is the upper and lower epidermis, or leaf skin (UE and LE). Photosynthesis occurs in the central spongy and palisade mesophyll cells(SP and PA, respectively). Veins (V) for water and sugartransport are wrapped in a ring of cells known as the bundle sheath (BS) which extend to the epidermis to the epidermis (bundle sheathextensions; BSE). Cells measured in the cross-section can be mathematically modelled in 3-D as cylinders, capsules or spheres. It is rare in biology that a single trait can answer questions spanning severalfields of research. One such trait is plant biology's"leaf mass per area," a simple measurement ...

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Lepidodendron: Habit and Habitat of Lepidodendron: A new groups of arborescent lycopods, popularly known as Lepidodendrales, had evolved from the Middle Devonian lycopods. These arborescent plants would grow to 164 ft (50 m) and form extensive coal measures swamp forest of the Northern Hemisphere Euramerican province during the Carboniferous period. Among these, Lepiclodendron was the most successful of all the arborescent members and is the best-investigated genus (Fig. 7.36). In early stage of development, an endosporic prothallus grew straight up and subsequently it expanded its diameter by secondary growth until its apical meristem divided. Thus, in the successive dichotomy, the size of the branches decreased until the growth finally ceased with terminal twig. So the plant had a determinate growth pattern. The Lepidodendron was a large tree (50-60 m tall) with a prominent trunk (up to 35 m height). The ultimate dichotomies formed the leaves. The branches and the foliage...

In this article we will discuss about Fossils . Contents: 1. Meaning of Fossils 2. Formation of Fossils 3. Types Various Names Assigned to Fossils 4. How are Fossils Studies? 5. How are Fossils Reconstructed and Named? 6. Determination of Age of Fossils   1 . Meaning of Fossils Remains or vestiges or traces of plants and animals of the past are called fossils. These remains of organisms from past geological ages remain preserved in sedimentary rocks either as actual structures or as impressions, casts or molds. The word ‘fossil’ is derived from the Latin word “fossilis” which means “to dig up”. In the earlier studies, therefore, a large number of things dug out of earth’s crust were called fossils. These things also included minerals and rocks besides remains of plants and animals. Later on, however, study of fossils were made restricted to only animals and plants. Study of fossils is of great importance because: (i) They furnish evidence of the prehistoric life, an...

RHYNIA; The fossil Pteridophyta Above: Transverse sections through axes of Rhynia gwynne-vaughanii . The star-shaped axes, right of centre, are a result of shrinkage during decay and desiccation of the stems (scale bar = 1mm).   Introduction One of the first Rhynie chert plants to be described and perhaps the most abundant is the form Rhynia . The plant was originally described and classified by Kidston and Lang in 1917 , 1920a and assigned the species name Rhynia gwynne-vaughanii . Another plant now known as Aglaophyton , possessing a slightly similar anatomy, was originally described by Kidston and Lang in their 1917 paper as also belonging to Rhynia gwynne-vaughanii , but differs significantly in its vascular anatomy and was subsequently reassigned (see also Aglaophyton ). Unequivocal gametophytes of Rhynia have recently been discovered ( Kerp et al . in press ) and will be illustrated here once published. The over...

Basically in +3 level or in graduation level biological students come across various fundamental topics  on biology.It's my first blog and I'm going to publish some posts on this blog about some biological topic. I will describe about the pteridophytes in my next blog and please stay connected with me.                                                                                                                                                    THANK YOU