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haplostele – consisting of a cylindrical core of xylem surrounded by a ring of phloem. An endodermis generally surrounds the stele. An endodermis generally surrounds the stele. A centrarch (protoxylem in the center of a metaxylem cylinder) haplostele is prevalent in members of the rhyniophyte grade, such as Rhynia .
Psilotum is a genus of fern-like vascular plants.It is one of two genera in the family Psilotaceae commonly known as whisk ferns, the other being Tmesipteris.Plants in these two genera were once thought to be descended from the earliest surviving vascular plants, but more recent phylogenies place them as basal ferns, as a sister group to Ophioglossales.
The hard palate is formed by the palatine process of the maxilla and horizontal plate of palatine bone.It forms a partition between the nasal passages and the mouth.On the anterior portion of the hard palate are the plicae, irregular ridges in the mucous membrane that help hold food while the teeth are biting into it while also facilitating the movement of food backward towards the larynx once ...
The decapod (crustaceans such as a crab, lobster, shrimp or prawn) is made up of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (). [1] [2] Each segment may possess one pair of appendages, although in various groups these may be reduced or missing.
The salivary glands (element 30 in numbered diagram) in an insect's mouth produce saliva. The salivary ducts lead from the glands to the reservoirs and then forward through the head to an opening called the salivarium, located behind the hypopharynx. By moving its mouthparts (element 32 in numbered diagram) the insect can mix its food with saliva.
The idea of a tree of life arose from ancient notions of a ladder-like progression from lower into higher forms of life (such as in the Great Chain of Being).Early representations of "branching" phylogenetic trees include a "paleontological chart" showing the geological relationships among plants and animals in the book Elementary Geology, by Edward Hitchcock (first edition: 1840).
The standard anatomical position, or standard anatomical model, is the scientifically agreed upon reference position for anatomical location terms.Standard anatomical positions are used to standardise the position of appendages of animals with respect to the main body of the organism.
The greater omentum (also the great omentum, omentum majus, gastrocolic omentum, epiploon, or, especially in non-human animals, caul) is a large apron-like fold of visceral peritoneum that hangs down from the stomach.