Pith

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Pith

Pith is a light substance that is found in vascular plant

Vascular plant

Vascular plants are those plants that have lignin tissue for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the ferns, clubmosses, flowering plants, conifers and other gymnosperms....
s.

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Pith is a light substance that is found in vascular plant

Vascular plant

Parenchyma

Parenchyma is a term used to describe a bulk of a substance. It is used in different ways in animals and in plants.The term is New Latin, from Greek language parenkhuma, visceral flesh, from parenkhein, to pour in beside : para-, beside + en-, in + khein, to pour....
cells, and is located in the center of the stem

Plant stem

A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaf, inflorescence , conifer cones or other stems etc....
. It is encircled by a ring of xylem

Xylem

In vascular plants, xylem is one of the two types of transport tissue, phloem being the other. The word "xylem" is derived from classical Greek language ????? , "wood", and indeed the best known xylem tissue is wood, though it is found throughout the plant....
(wood

Wood

Wood is an organic material; in the strict sense wood is produced as secondary xylem in the stems of woody plants, notably trees but also shrubs, etc....
y tissue), and outside that, a ring of phloem

Phloem

In vascular plants, phloem is the living Biological tissue that carries organic nutrients , particularly sucrose, a sugar, to all parts of the plant where needed....
(bark

BARK

BARK was an early Electromechanics. BARK was built using standard phone relays, implementing a 32-bit binary machine and could perform addition in 150 ms and multiplication in 250 ms....
tissue). In most plants the pith is solid, but some plants, e.g. grasses

Poaceae

Poaceae or Gramineae is a family in the Class Liliopsida of the Magnoliophyta. Plants of this family are usually called grasses; the shrub- or tree-like plants in this family are called bamboo ....
and umbellifers

Apiaceae

The Apiaceae or Umbelliferae is a family of usually aromatic plants with hollow stems, commonly known as umbellifers. It includes cumin, parsley, carrot, coriander/cilantro, dill, caraway, fennel, parsnip, celery, Queen anne's lace and other relatives....
, the pith has a hollow centre forming a hollow tube except at the points where leaves

Leaf

In botany, a leaf is an above-ground plant Organ specialized for photosynthesis. For this purpose, a leaf is typically flat and thin, to expose the cells containing chloroplast to light over a broad area, and to allow light to penetrate fully into the tissues....
are produced, where there is a solid plate across the stem. A few plants, e.g. walnut

Walnut

Walnuts are plants in the family Juglandaceae. They are deciduous trees, 10–40 meter s tall , with pinnate leaves 200?900 millimetres long , with 5–25 leaflets; the shoots have chambered pith, a character shared with the wingnut but not the hickory in the same family....
, have distinctive chambered pith with numerous short cavities in the pith.

The word comes from the Old English word piþa, meaning substance, akin to Middle Dutch

Middle Dutch

Middle Dutch is a collective name for a number of closely related West Germanic dialects which were spoken and written between 1150 and 1500. There was at that time as yet no overarching standard language, but they were all mutually intelligible....
pit, meaning the pit of a fruit.

The pith varies in diameter from about 0.5 mm to 6-8 mm in solid pith, and up to 150 mm or more in the stems of some plants with hollow pith, e.g. some bamboo

Bamboo

The bamboos are a group of woody perennial plant evergreen plants in the true grass family Poaceae, subfamily Bambusoideae, tribe Bambuseae....
s. Freshly grown pith in young new shoots is typically white or pale brown, commonly darkening with age. In woody plant

Woody plant

A woody plant is a Vascular tissue plant that has a Perennial plant Plant stem that is above ground and covered by a layer of thickened bark. Woody plants are adapted to survive from one year to the next; the stem supports continued vegetative growth above ground from one year to next....
s (tree

TREE

TREE was a Boston hardcore punk band formed in the summer of 1990. They were active in the Boston music scene until disbanding in 2002....
s, shrub

Shrub

A shrub or bush is a horticulture rather than strictly Botany category of woody plant, distinguished from a tree by its multiple stems and lower height, usually less than 5-6 m tall....
s), the pith becomes surrounded by successive annual layers of wood; it may be very inconspicuous but is always present at the center of a trunk or branch. The cells in the peripheral parts of the pith may in some plants (e.g. Hedera
Ivy

Hedera is a genus of 15 species of climbing or ground-creeping evergreen woody plants in the family Araliaceae, native to the Macaronesia, western, central and southern Europe, northwestern Africa and across central-southern Asia east to Japan....
helix) develop to be different from cells in the rest of the pith. This layer of cells is then called the perimedullary region of the pithamus.

The pith of the sola

Aeschynomene aspera

Aeschynomene aspera is a species of flowering plant in the family Fabaceae. It is also known by the names Sola, Sola Pith Plant, Pith Plant, Laugauni or Netti ...
or other similar plants is used to make the pith helmet

Pith helmet

The pith helmet is a lightweight helmet made of cork or pith, typically from the sola or a similar plant , with a cloth cover, designed to shade the wearer's head from the sun....
.

The pith of some plants, such as sago

Sago

Sago is a starch extracted from the pith of sago palm stems, Metroxylon sagu. It is a major staple food for the lowland peoples of Papua New Guinea and the Moluccas, where it is called saksak and sagu....
, is edible to humans.

The inner rind or albedo of hesperidium

Hesperidium

A hesperidium is a modified berry with a tough, leathery rind. The peel contains volatile oil glands in pits. The fleshy interior is composed of separate sections, called carpels, filled with fluid-filled vesicles that are actually specialized hair cells....
is also called pith.