''Acampe rigida'' is a species of

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowerin ...

native to the forests of tropical southern Asia where it grows on trees and rocks at altitudes of up to .

Description

38 Acampe rigida (as Vanda multiflora) - John Lindley - Collectanea botanica (1821)

''Acampe rigida'' is a robust species with an unbranched stem up to in length and in diameter. The leaves are

distichous In botany, phyllotaxis () or phyllotaxy is the arrangement of leaves on a plant stem. Phyllotactic spirals form a distinctive class of patterns in nature. Leaf arrangement The basic arrangements of leaves on a stem are opposite and alterna ...

. The stem nodes are about apart and each bears a somewhat fleshy, upright leaf with sheathing base. The apices of the leaves are obtuse and unequally bilobed. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...

is unbranched or sparsely branched, with many slightly fragrant, upturned, cup-shaped flowers less than in diameter. The petals are fleshy, and are yellow with purplish-brown stripes; they have a thick, white, three-lobed lower lip, and a short spur. They are followed by cylindrical or fusiform capsules.

Distribution and habitat

''Acampe rigida'' is native to the Andaman Islands,

Assam Assam (; ) is a state in northeastern India, south of the eastern Himalayas along the Brahmaputra and Barak River valleys. Assam covers an area of . The state is bordered by Bhutan and Arunachal Pradesh to the north; Nagaland and Manipur ...

Bangladesh Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...

Bhutan Bhutan (; dz, འབྲུག་ཡུལ་, Druk Yul ), officially the Kingdom of Bhutan,), is a landlocked country in South Asia. It is situated in the Eastern Himalayas, between China in the north and India in the south. A mountainou ...

Cambodia Cambodia (; also Kampuchea ; km, កម្ពុជា, UNGEGN: ), officially the Kingdom of Cambodia, is a country located in the southern portion of the Indochinese Peninsula in Southeast Asia, spanning an area of , bordered by Thailan ...

, China,

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

, Laos,

Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...

Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...

Nepal Nepal (; ne, :ne:नेपाल, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne, सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in S ...

, the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

, Sri Lanka,

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...

and

Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making i ...

.Kew World Checklist of Selected Plant Families
/ref>Flora of China v 25 p 449, 多花脆兰 duo hua cui lan, ''Acampe rigida'' (Buchanan-Hamilton ex Smith) P. F. Hunt, Kew Bull. 24: 98. 1970.
/ref> It occurs in forests, either growing

epiphytically 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 around it. The plants on which epiphytes grow are called phoroph ...

on the branches and trunks of trees, or growing on rocks, and often forming dense clumps. Its altitudinal range is from .

Ecology

''Acampe rigida'' is a deceptive orchid in that it produces a fragrance that may attract insects but does not then offer them any reward. It is self-compatible, but has not evolved any particular mechanism to enable

self-pollination Self-pollination is a form of pollination in which pollen from the same plant arrives at the stigma of a flower (in flowering plants) or at the ovule (in gymnosperms). There are two types of self-pollination: in autogamy, pollen is transferred ...

. In Guangxi province in southwestern China, it flowers in late August and September, at a time of year when rain falls almost daily and insect pollinators are scarce. In a research study, after many hours of observation, a single insect was observed to visit a flower, but pollination did not occur. Instead, the plant exhibited ombrophily; rain drops falling on the tips of the stamens knocked the caps off the anthers, and further drops caused the

pollinia A pollinium (plural pollinia) is a coherent mass of pollen grains in a plant that are the product of only one anther, but are transferred, during pollination, as a single unit. This is regularly seen in plants such as orchids and many species of mil ...

to be ejected upwards, after which strap-like stipes arrested their movement and caused them to land in the stigma cavity, resulting in self-pollination. A high rate of fruit set occurred, but without the action of the raindrops, self-pollination did not occur and fruit did not set.

References

External links

* * {{Taxonbar, from=Q3336674 rigida Orchids of Asia Plants described in 1818