''Micromelum'' is a genus of eight species of flowering plants in the family

Rutaceae The Rutaceae () is a family (biology), family, commonly known as the rueRUTACEAE
in Bo ...

Description

The genus includes evergreen and deciduous shrubs and trees. The leaves are glandular and aromatic, containing essential oils. They are alternately arranged. They are usually

pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and ...

, divided into up to 23 leaflets, except for ''M. diversifolium'', which sometimes has undivided leaf blades. The leaflet edges are smooth or toothed. There are sometimes glandular

stipule In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole (botany), petiole). They are primarily found among dicots and rare among monocots. Stipules are considered part ...

s. The

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

is a large

panicle In botany, a panicle is a much-branched inflorescence. (softcover ). Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers (and fruit) be pedicellate (having a single stem per flower). The branches of a p ...

, sometimes flat-topped like a

corymb Corymb is a botanical term for an inflorescence with the flowers growing in such a fashion that the outermost are borne on longer pedicels than the inner, bringing all flowers up to a common level. A corymb has a flattish top with a superficial re ...

, growing from the or at the ends of branches. The flowers have five narrow petals in shades of green, white, or yellow, borne in a hairy, cup-like with five lobes or five separate

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' ...

s. The odour of the flowers has been described as "malodorous" and "foetid". There are ten

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s and one to five styles. The genus is noted for the unusual curving or twisting of the chambers in the

ovary The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/ oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are end ...

. The fruit is a

berry A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit although many pips or seeds may be present. Common examples of berries in the cul ...

up to long. It is yellow, orange, or red, and sometimes fleshy, but it lacks the pulp present in some related fruits, notably citrus. The peel is gland-dotted. Each fruit has one to three seeds. The plants vary in form, with ''M.. hirsutum'' being a low shrub sometimes less than tall and '' M. integerrimum'' being a tree which can exceed in height.

Taxonomy

The genus ''Micromelum'' was first formally described in 1825 by

Carl Ludwig Blume Charles Ludwig de Blume or Karl Ludwig von Blume (9 June 1796 – 3 February 1862) was a German-Dutch botanist and entomologist who spent most of his professional life in the Netherlands and the Dutch East Indies. As deputy director of agricul ...

in '' Bijdragen tot de Flora van Nederlandsch Indie'' and the first species described was ''Micromelum pubescens'', now regarded as a

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of '' Micromelum minutum''. There are several

subfamilies In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zool ...

in the citrus family, with genus ''Citrus'' classified in the

Aurantioideae Aurantioideae (sometimes known as Citroideae) is the subfamily within the rue and citrus family (biology), family (Rutaceae) that contains the citrus. The subfamily's center of diversity is in the monsoon region of eastern Australasia, extending ...

. ''Micromelum'' belongs to the other tribe in this subfamily,

Clauseneae Clauseneae is one of the two tribes of the flowering plant family Rutaceae, subfamily Aurantioideae, the other being Citreae, which includes ''Citrus''. The tribe comprises five genera: '' Micromelum'', '' Glycosmis'', '' Clausena'', '' Murray ...

. It is the only genus of the subtribe Micromelinae that are known technically as the "very remote citroid fruit trees".Swingle, W. T., rev. P. C. Reece
Chapter 3: The Botany of ''Citrus'' and its Wild Relatives.
In: ''The Citrus Industry'' vol. 1. Webber, H. J. (ed.). Berkeley: University of California Press. 1967. ''Micromelum'' includes eight species distributed in Asia, Australia, and the Pacific Islands.''Micromelum''.
Flora of China.
College of Natural and Agricultural Sciences. University of California, Riverside.

Species list

The following is a list of species and varieties accepted at the

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

as at July 2020: * '' Micromelum compressum''

Blanco Blanco (''white'' or ''blank'' in Spanish) or Los Blancos may refer to: People *Blanco (surname) Fictional characters *Blanco, a hobbit in J. R. R. Tolkien's Middle-earth *Blanco Webb, character in the BBC sitcom ''Porridge'' *Graboid#El Blanco, ...

– Vietnam * '' Micromelum coriaceum'' Seem. – New Caledonia * '' Micromelum diversifolium'' Miq. * '' Micromelum glanduliferum'' B.Hansen – Laos, Thailand * '' Micromelum hirsutum'' Oliv. – Bangladesh, Laos, Malaya, Myanmar, Vietnam * '' Micromelum integerrimum'' ( Roxb. ex DC.)

Wight A wight is a being or thing. This general meaning is shared by cognate terms in Germanic languages, however the usage of the term varies greatly over time and between regions. In Old English, it could refer to anything in existence, with more s ...

Arn. George Arnott Walker Arnott of Arlary (6 February 1799 – 17 April 1868) was a Scottish botanist. He collaborated with botanists from around the world and served as a regius professor of botany at the University of Glasgow. An orchid genus ' ...

ex M.Roem. – Andaman Is., Cambodia, China South-Central, China Southeast, East Himalaya, Hainan, Laos, Myanmar, Nepal, Philippines, Thailand, Tibet, Vietnam * '' Micromelum minutum'' ( G.Forst.) Wight & Arn. – Assam, Bangladesh, Cambodia, China South-Central, China Southeast, Fiji, Hainan, Laos, Lesser Sunda Is., Malaya, Myanmar, New Caledonia, Niue, Samoa, Solomon Is., Thailand, Tonga, Vanuatu, Vietnam, Wallis-Futuna Is., Australia ** ''Micromelum minutum'' var. ''ceylanicum'' B.C.Stone – Sri Lanka * '' Micromelum scandens'' Rech. – Bismarck Archipelago

Chemistry

''M. minutum'' is used as a traditional medicine in Fiji, and in Malaysia it is used to treat fever and ringworm.Ito, C., et al. (2000)
Chemical constituents of ''Micromelum minutum''. Isolation and structural elucidation of new coumarins.
''Chemical and Pharmaceutical Bulletin - Tokyo'' 48(3), 334-38. ''M. integerrimum'' has been used in China to treat dysentery and arthritis.He, H. P., et al. (2001)
Three new coumarins from ''Micromelum integerrimum''.
''Chinese Chemical Letters'' 12(7) 603-06. The chemistry of these plants has been studied, with several known and new

coumarin Coumarin () or 2''H''-chromen-2-one is an aromatic organic chemical compound with formula . Its molecule can be described as a benzene molecule with two adjacent hydrogen atoms replaced by an unsaturated lactone ring , forming a second six-me ...

s isolated. One such coumarin from ''M. integerrimum'', micromelin, appears to have anticancer properties.

References

{{Taxonbar, from=Q9032437 Aurantioideae genera Aurantioideae Taxa named by Carl Ludwig Blume