botany Botany, also called , 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 "botany" comes from the Ancient Greek wo ...

botany

, a bulb is structurally a short

stem Stem or STEM may refer to: Biology * Plant stem, the aboveground structures that have vascular tissue and that support leaves and flowers ** Stipe (botany), a stalk that supports some other structure ** Stipe (mycology), the stem supporting the c ...

stem

with fleshy

leaves A leaf (plural leaves) is the principal lateral appendage of the vascular plant plant stem, stem, usually borne above ground and specialized for photosynthesis. The leaves, stem, flower and fruit together form the shoot system. Leaves are ...

leaves

or leaf basesBell, A.D. 1997. ''Plant form: an illustrated guide to flowering plant morphology''. Oxford University Press, Oxford, U.K. that function as

food Food is any substance consumed to provide Nutrient, nutritional support for an organism. Food is usually of plant, animal or Fungus, fungal origin, and contains essential nutrients, such as carbohydrates, fats, protein (nutrient), proteins, vi ...

food

storage organ A storage organ is a part of a plant Plants are predominantly photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fung ...

s during

dormancy Dormancy is a period in an organism's life cycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia *Biological life cycle, the sequence of life stages that an organism undergoes from birth to reproduction ending with the pr ...

. (In

gardening Gardening is the practice of growing and cultivating plants as part of horticulture Horticulture is the art of cultivating plants in gardens to produce food and medicinal ingredients, or for comfort and ornamental purposes. Horticulturists ar ...

, plants with other kinds of storage organ are also called "

ornamental bulbous plant Ornamental bulbous plants, often called ornamental bulbs or just bulbs in gardening and horticulture, are herbaceous Perennial plant, perennials grown for ornamental purposes, which have underground or near ground storage organs. Botanists dis ...

s" or just "bulbs".)

Description

The bulb's leaf bases, also known as scales, generally do not support leaves, but contain food reserves to enable the plant to survive adverse conditions. At the center of the bulb is a vegetative growing point or an unexpanded flowering shoot. The base is formed by a reduced

, and plant growth occurs from this basal plate.

Root In vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia artēria'' 'windpipe' + φυτά ''phutá'' 'plants'), form a large grou ...

Root

s emerge from the underside of the base, and new stems and leaves from the upper side. Tunicate bulbs have dry, membranous outer scales that protect the continuous lamina of fleshy scales. Species in the genera ''

Allium ''Allium'' is a genus of monocotyledonous flowering plants that includes hundreds of species, including the cultivated onion, garlic, scallion, shallot, leek, and chives. The Generic name (biology), generic name ''Allium'' is the Latin word for ...

Allium

'', ''

Hippeastrum ''Hippeastrum'' () is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonom ...

'', ''

Narcissus Narcissus may refer to: Biology * Narcissus (plant), ''Narcissus'' (plant), a genus containing daffodils and others People * Narcissus (mythology), Greek mythological character * Narcissus (wrestler) (2nd century), assassin of the Roman emperor Co ...

'', and ''

Tulip Tulips (''Tulipa'') are a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology Biology is the natural science that studies life and living organisms, inclu ...

Tulip

a'' all have tunicate bulbs. Non-tunicate bulbs, such as ''

Lilium ''Lilium'' is a genus of Herbaceous plant, herbaceous flowering plants growing from bulbs, all with large prominent flowers. They are the true lilies. Lilies are a group of flowering plants which are important in culture and literature in much o ...

Lilium

'' and ''

Fritillaria ''Fritillaria'' (fritillaries) is a genus of spring flowering herbaceous bulbous perennial plants in the lily family (biology), family (Liliaceae). The type species, ''Fritillaria meleagris'', was first described in Europe in 1571, while other ...

'' species, lack the protective tunic and have looser scales. Bulbous plant species cycle through vegetative and reproductive growth stages; the bulb grows to flowering size during the vegetative stage and the plant flowers during the reproductive stage. Certain environmental conditions are needed to trigger the transition from one stage to the next, such as the shift from a cold winter to spring. Once the flowering period is over, the plant enters a foliage period of about six weeks during which time the plant absorbs nutrients from the soil and energy from the sun for setting flowers for the next year. Bulbs dug up before the foliage period is completed will not bloom the following year but then should flower normally in subsequent years.

Plants that form bulbs

Plants that form underground

s, including bulbs as well as

tuber Tubers are enlarged structures used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing season, and ...

s and

corm A corm, bulbo-tuber, or bulbotuber is a short, vertical, swollen underground plant stem '' has lost its leaves, but is producing adventitious rootsImportant structures in plant development are buds, shoots, root In vascular plants, the ro ...

corm

s, are called ''geophytes''. Some

epiphytic 200px, '' Tillandsia bourgaei'' growing on an oak tree in Mexico An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating a ...

orchid Orchidaceae ( ), commonly called the orchid family, is a diverse and widespread family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social ...

orchid

s (family

Orchidaceae Orchidaceae ( ), common name, commonly called the orchid family, is a diverse and widespread family (biology), family of flowering plants, with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two la ...

) form above-ground storage organs called ''

pseudobulb The pseudobulb is a storage organ A storage organ is a part of a plant Plants are predominantly photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not a ...

s'', that superficially resemble bulbs. Nearly all plants that form true bulbs are

monocotyledon 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 Embryo#Plant embryos, embryonic leaf, or cotyledon. Th ...

s, and include: * ''

Amaryllis ''Amaryllis'' () is the only genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classificati ...

'', ''

Crinum ''Crinum'' is a genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classification. The term may also refer to a ...

Crinum

'', ''

'', and several other members of the amaryllis family

Amaryllidaceae The Amaryllidaceae are a family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group sharing the same spatial or social territory, typic ...

. This includes

onion The onion (''Allium cepa'' L., from Latin ''cepa'' "onion"), also known as the bulb onion or common onion, is a vegetable Vegetables are parts of plants that are consumed by humans or other animals as food. The original meaning is still com ...

onion

garlic Garlic (''Allium sativum'') is a species of bulbous flowering plant in the genus ''Allium''. Its close relatives include the onion, shallot, leek, chive, Allium fistulosum, Welsh onion and Allium chinense, Chinese onion. It is native to Central ...

garlic

, and other

allium ''Allium'' is a genus of monocotyledonous flowering plants that includes hundreds of species, including the cultivated onion, garlic, scallion, shallot, leek, and chives. The Generic name (biology), generic name ''Allium'' is the Latin word for ...

allium

s, members of the Amaryllid subfamily

Allioideae Allioideae is a subfamily 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 Embryo#Plant e ...

. *

Lily ''Lilium'' is a genus of Herbaceous plant, herbaceous flowering plants growing from bulbs, all with large prominent flowers. They are the true lilies. Lilies are a group of flowering plants which are important in culture and literature in much ...

Lily

tulip Tulips (''Tulipa'') are a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology Biology is the natural science that studies life and living organisms, inclu ...

tulip

, and many other members of the lily family

Liliaceae The lily family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group sharing the same spatial or social territory, typically subject ...

. * Two groups of ''

Iris

'' species, family

Iridaceae Iridaceae is a family of plants in order Asparagales Asparagales (asparagoid lilies) is an order (biology), order of plants in modern classification systems such as the Angiosperm Phylogeny Group (APG) and the Angiosperm Phylogeny Web. The ord ...

: subgenus '' Xiphium'' (the "Dutch" irises) and subgenus '' Hermodactyloides'' (the miniature "rock garden" irises). ''

Oxalis ''Oxalis'' ( (American English) or (British English)) is a large genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Vi ...

Oxalis

'', in the family

Oxalidaceae The Oxalidaceae, or wood sorrel family, are a small family of five genera of herb In general use, herbs are plants with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal purposes, or for fragrances; e ...

, is the only

dicotyledon The dicotyledons, also known as dicots (or more rarely dicotyls), are one of the two groups into which all the flowering plant The flowering plants, also known as Angiospermae (), or Magnoliophyta (), are the most diverse group of Embryophyte ...

genus that produces true bulbs.

Bulbil

bulbil A bulbil (also referred to as bulbel, bulblet, and/or pup) is a small, young plant that is reproduced vegetatively from axillary bud The axillary bud (or lateral bud) is an Plant embryogenesis, embryonic or Organogenesis#Plant organogenesis, org ...

is a small bulb, and may also be called a bulblet, bulbet, or bulbel. Small bulbs can develop or propagate a large bulb. If one or several moderate-sized bulbs form to replace the original bulb, they are called renewal bulbs. Increase bulbs are small bulbs that develop either on each of the leaves inside a bulb, or else on the end of small underground stems connected to the original bulb. Some lilies, such as the tiger lily ''

Lilium lancifolium

'', form small bulbs, called bulbils, in their leaf

axil A leaf (plural leaves) is the principal lateral appendage of the vascular plant plant stem, stem, usually borne above ground and specialized for photosynthesis. The leaves and stem together form the shoot. Leaves are collectively referred ...

s. Several members of the onion family, Alliaceae, including ''Allium sativum'' (

), form bulbils in their flower heads, sometimes as the flowers fade, or even instead of the flowers (which is a form of

apomixis In botany, apomixis is asexual reproduction without fertilization. Its etymology is Greek for "away from" + "mixing". This definition notably does not mention meiosis. Thus "normal Plant reproduction#Asexual reproduction, asexual reproduction" o ...

). The so-called

tree onion The tree onion (''Allium'' × ''proliferum'') is a plant similar to the common onion (''A. cepa''), but with a cluster of bulblets where a normal onion would have flowers. Tree onions are also known as topsetting onions, walking onions, or Eg ...

(''Allium'' × ''proliferum'') forms small onions which are large enough for

pickling Pickling is the process of preserving or extending the shelf life of food Food is any substance consumed to provide Nutrient, nutritional support for an organism. Food is usually of plant, animal or Fungus, fungal origin, and contains ess ...

. Some ferns, such as the hen-and-chicken fern, produce new plants at the tips of the fronds' pinnae that are sometimes referred to as bulbils. Image:Lilium lancifolium bulbils.jpg, Bulbils form in the leaf axils of ''

Lilium lancifolium

'' Image:Alliumvineale1web.jpg, Wild garlic (''

Allium vineale

'') bulbils sprouting Image:Allium fistulosum bulbifera0.jpg, "

Tree onion The tree onion (''Allium'' × ''proliferum'') is a plant similar to the common onion (''A. cepa''), but with a cluster of bulblets where a normal onion would have flowers. Tree onions are also known as topsetting onions, walking onions, or Eg ...

s" form clusters of small bulbs instead of flowers

References

{{botany

Plant morphology ''Plant morphology'' is the field in botany that studies the diversity in forms, with the naked eye or slight optical magnification. This is opposed to plant anatomy (see :Plant anatomy) that needs to cut into plants to be able to study its subject, ...

Garden plants

Plant reproduction {{Commons cat, Plant reproduction Plants, reproduction Horticultural techniques Reproduction, .Plant ...

Description

Plants that form bulbs

Bulbil

Further reading

References