botany Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...

, a fascicle is a bundle of

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

or flowers growing crowded together; alternatively the term might refer to the

vascular tissue Vascular tissue is a complex transporting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue are the xylem and phloem. These two tissues transport fluid and nutrients internally. T ...

s that supply such an organ with nutrients.Shashtri, Varun. Dictionary of Botany. Publisher: Isha Books 2005. However, vascular tissues may occur in fascicles even when the organs they supply are not fascicled.

Etymology of fascicle and related terms

The term ''fascicle'' and its derived terms such as ''fasciculation'' are from the Latin ''fasciculus'', the diminutive of ''fascis'', a bundle. Accordingly, such words occur in many forms and contexts wherever they are convenient for descriptive purposes. A fascicle may be leaves or flowers on a short shoot where the nodes of a shoot are crowded without clear internodes, such as in species of ''

Pinus A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. ''World Flora Online'' accepts 134 species-rank taxa (119 species and 15 nothospecies) of pines as c ...

'' or '' Rhigozum''. However, bundled fibres, nerves or bristles as in tissues or the glochid fascicles of ''

Opuntia ''Opuntia'', commonly called the prickly pear cactus, is a genus of flowering plants in the cactus family Cactaceae, many known for their flavorful fruit and showy flowers. Cacti are native to the Americas, and are well adapted to arid clima ...

'' may have little or nothing to do with branch morphology.

In pines

Leaf fascicles are present in all

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. ''World Flora Online'' accepts 134 species-rank taxa (119 species and 15 nothospecies) of pines as cu ...

s, and the number of adult leaves (needles) per fascicle is an important character for identification of pine

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

and

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

. Most species have fascicles of 2 to 5 needles; only occasional species typically have as few as one or as many as six leaves to the fascicle. Variation is high between species, low within them. For example, '' Pinus flexilis'' ( limber pine), has fascicles of 5 needles. This pine is a member of the white pine group, ''

'' subgenus '' Strobus'', section '' Strobus''. In all members of the group the fascicles nearly all have five needles and the sheath at the base of the fascicle is deciduous. The fascicle sheath is another character that is important for identification. Among

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

n pines the sheath is persistent in all so-called hard pines and deciduous in all so-called soft pines. Thus, the fascicle sheath and number of needles can be used to identify valuable

timber Lumber is wood that has been processed into uniform and useful sizes (dimensional lumber), including beams and planks or boards. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, window frames). ...

pines in all seasons and many years before they are mature enough to produce cones. These two characters readily distinguish the major groups of pines (see ''Pinus'' classification). '' Pinus durangensis'' ( Durango pine) has fascicles of 6 needles, rarely 7, and is the only species in ''

'' with so many needles per fascicle. At the other extreme, '' Pinus monophylla'' has fascicles of one needle, rarely two. This is the only species of pine with just one needle per fascicle, and this rare and easily observed character is reflected in the

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''monophylla'' and in the

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...

single-leaf pinyon. Although it might strike non-botanists as illogical to apply the term "fascicle" to a stem bearing a single leaf, the justification is that the structure of the stem is consistent with other pine fascicles, which justifies generalising the term to embrace single-needle fascicles as well.

In flowering plants

Lavandula peduncle showing fascicles of flowers 2012 04 11 5758

Fascicles do occur in some

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s, though not as frequently as in many conifers. Consequently, when fascicles are present the specific epithet often refers to them. Examples include '' Prunus fasciculata'' and '' Adenostoma fasciculatum''. Species with flowers in fascicles include '' Aechmea biflora'' and ''

Melicytus ramiflorus ''Melicytus ramiflorus'', commonly known as māhoe, is a small tree of the family Violaceae. It is endemic (ecology), endemic to New Zealand. It grows up to 10 metres high with a trunk up to 60 cm in diameter, it has smooth, light bark a ...

'', several species of '' Malva'', and the entire genus '' Flueggea''. Some species of the family Alseuosmiaceae have flowers in fascicles. In the Bignoniaceae in the genus Rhigozum flowers are borne in fascicles from cushion-like, dwarf branchlets in the axils of leaves, and several species also bear leaves in fascicles on similar or shared branchlets.Dyer, R. Allen, “The Genera of Southern African Flowering Plants”. , 1975 Both leaf and flower fascicles occur among Angiospermae, often as

adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the p ...

s facilitating

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma (botany), stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or bu ...

, such as in many

Lamiaceae The Lamiaceae ( ) or Labiatae are a family (biology), family of flowering plants commonly known as the mint, deadnettle, or sage family. Many of the plants are aromatic in all parts and include widely used culinary herbs like basil (herb), ba ...

, of which some '' Lavandula'' are typical. Other plant fascicles are adaptations to achieve greater compactness for defensive reasons. For example, in ''

'' cacti, spines are produced in fascicles bearing a few long spines and many short spiny bristles (or glochids).

In lower plants

Sphagnum ''Sphagnum'' is a genus of approximately 380 accepted species of mosses, commonly known as sphagnum moss, also bog moss and quacker moss (although that term is also sometimes used for peat). Accumulations of ''Sphagnum'' can store water, since ...

'' species bear branches in fascicles.

References

{{reflist Plant anatomy Plant morphology

Etymology of fascicle and related terms

In pines

In flowering plants

In lower plants

See also

References