A spikelet, in

botany Botany, also called plant science (or plant sciences), plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "bot ...

, describes the typical arrangement of the flowers of

grasses Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns a ...

, sedges and some other

Monocot Monocotyledons (), commonly referred to as monocots, ( Lilianae '' sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute on ...

s. Each spikelet has one or more florets. The spikelets are further grouped into panicles or spikes. The part of the spikelet that bears the florets is called the

rachilla Rachilla may refer to the following topics in botany: * Rachilla (floral axis) A spikelet, in botany, describes the typical arrangement of the flowers of grasses, sedges and some other Monocots. Each spikelet has one or more florets. The spikele ...

In grasses

In Poaceae, the grass

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

, a spikelet consists of two (or sometimes fewer) bracts at the base, called glumes, followed by one or more florets. A floret consists of the flower surrounded by two bracts, one external—the lemma—and one internal—the palea. The perianth is reduced to two scales, called lodicules, that expand and contract to spread the lemma and palea; these are generally interpreted to be modified sepals. The flowers are usually hermaphroditic—

maize Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn ( North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. ...

being an important exception—and mainly anemophilous or wind-pollinated, although insects occasionally play a role.

Lemma

Lemma is a phytomorphological term referring to a part of the spikelet. It is the lowermost of two chaff-like bracts enclosing the grass floret. It often bears a long bristle called an awn, and may be similar in form to the

glume In botany, a glume is a bract (leaf-like structure) below a spikelet in the inflorescence (flower cluster) of grasses (Poaceae) or the flowers of sedges (Cyperaceae). There are two other types of bracts in the spikelets of grasses: the lemma ...

s—chaffy bracts at the base of each spikelet. It is usually interpreted as a bract but it has also been interpreted as one remnant (the abaxial) of the three members of outer perianth

whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane flo ...

(the palea may represent the other two members, having been joined together). A lemma's shape, their number of veins, whether they are awned or not, and the presence or absence of hairs are particularly important

character Character or Characters may refer to: Arts, entertainment, and media Literature * ''Character'' (novel), a 1936 Dutch novel by Ferdinand Bordewijk * ''Characters'' (Theophrastus), a classical Greek set of character sketches attributed to The ...

s in grass taxonomy.

Palea

Palea, in Poaceae, refers to one of the bract-like organs in the spikelet. The palea is the uppermost of the two chaff-like bracts that enclose the grass floret (the other being the

lemma Lemma may refer to: Language and linguistics * Lemma (morphology), the canonical, dictionary or citation form of a word * Lemma (psycholinguistics), a mental abstraction of a word about to be uttered Science and mathematics * Lemma (botany), a ...

). It is often cleft at the tip, implying that it may be a double structure derived from the union of two separate organs. This has led to suggestions that it may be what remains of the grass sepals (outer perianth whorl): specifically the two adaxial members of the three membered whorl typical of

monocot Monocotyledons (), commonly referred to as monocots, ( Lilianae '' sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute on ...

s. The third member may be absent or it may be represented by the lemma, according to different botanical interpretations. The perianth interpretation of the palea is supported by the expression of MADS-box genes in this organ during development, as is the case in sepals of eudicot plants.Prasad, K, et al. (2005) OsMADS1, a rice MADS-box factor, controls differentiation of specific cell types in the lemma and palea and is an early-acting regulator of inner floral organs. The Plant Journal 43, 915–928

Lodicule

A lodicule is the structure that consists of between one and three small scales at the base of the ovary in a grass flower that represent the

corolla Corolla may refer to: *Corolla (botany), the petals of a flower, considered as a unit *Toyota Corolla, an automobile model name * Corolla (headgear), an ancient headdress in the form of a circlet or crown * ''Corolla'' (gastropod), a genus of moll ...

, believed to be a rudimentary perianth. The swelling of the lodicules forces apart the flower's bracts, exposing the flower's reproductive organs.

References

{{Authority control Plant morphology Poaceae

In grasses

Lemma

Palea

Lodicule

See also

References