Aiphanes

Aiphanes horrida

The thorn trees ( Aiphanes ), also Stilettpalmen, are a genus of 25 species of the palm family ( Arecaceae ), which are common in the Lesser Antilles, and from Venezuela to Bolivia along the Andes. Except for a style that reached Panama, lacks the sting palm trees in Central America. They fall on mainly by their up about 25 centimeters long spines that cover the plant almost complete.

  • 2.1 hazard
  • 3.1 pollination
  • 3.2 Seed dispersal
  • 6.1 Outer systematics
  • 6.2 Internal systematics 6.2.1 subgenus Macroanthera burret
  • 6.2.2 subgenus Brachyanthera burret
  • 6.2.3 Not allocated

Description

Sting Palms are perennial woody plants. Different types of branching palm trees can have different manifestations ( habitus ). Thus there are, for example, by A. erinaceae solitary standing individual trees, but also shrubby growth forms with over 20 tribes that are on open plains.

Characteristic features are about one millimeter to about 25 centimeters long spines, which almost cover the entire plant. Are reinforced stem, leaves and flower stalks and bracts of inflorescences. The spines are gray to black, with A. erinacea, A. simplex and A. tricuspidata but yellow. The spines grow from a group of round, thick-walled cells that initially form a thickening ( pulvinus ). Small spines are single cells with strongly thickened ( sklerenchymatisierter ) cell wall. Large spines consist of outer sclerenchyma cells and inner parenchyma.

The chromosome number is controversial, there are conflicting reports in the literature, such as for A. minima n = 15 or n = 18, and for A. horrida n = 16 or n = 15 Probably it is in the differences within a but kind artifacts. Probably, but not verified, n = 15 for the whole genus. For the closely related Acrocomia, Gastrococcus and Astrocaryum applies in any case n = 15

Root

Almost all species form from aboveground adventitious roots, which sometimes give the lower part of the stem cone shape. They are at the same time supporting roots and thus the same lack of secondary growth of the shoot axis. The adventitious roots are grayish to reddish brown and often branched. You can reach a diameter of between five and 15 millimeters. They are covered with whitish, wart-like lenticels that arise endogenously and are called Pneumatophore or breathing roots. They are used for gas exchange in very moist soil.

The exodermis is pronounced. The cortex consists mainly of parenchyma with irregular air-filled intercellular spaces. The endodermis is lignified. The stele is surrounded by Mark. So far, at A. macroloba, A. and A. are ulei Arbuscular mycorrhizal fungi weberbaueri in the root bark demonstrated.

Sprossachse

The shoot axis is branched or unbranched. They can be very short and are completely underground at A. acaulis and A. spicata. In A. grandis it is an elevation of 20 meters and reaches a diameter of up to 20 centimeters.

The trunk is always clearly marked by annular leaf scars and armed with spines that are circular or spiral around the nodes. The length of the internodes varies and reflects different growth speeds. For small species such as A. chiribogensis they are usually up to 15 inches long between one and two centimeters in the large species such as A. eggersii.

Branches arising from the basal ( underground or just above the earth's surface lying ) leaf axils or rarely distally directly from the stem axis.

The cross section corresponds to the characteristic construction of the monocots: the outside is the epidermis that surrounds a layer of primary cortex. This layer is usually very thin or barely present in A. But macroloba very pronounced and about 5 millimeters thick. Further inside is a cylinder of parenchyma in which distributed the vascular bundles run ( Ataktostele ). The outer part of the cylinder consists of black sclerenchyma.

Almost all species have a schraubige (disperse ) leaf position ( phyllotaxis ), only for A. linearis, A. verrucosa and A. lindeniana the leaves stand in two rows ( distich ). On young plants are available for all species, the leaves distichous, but loses quickly. The leaves are large fronds ( palm fronds ), their number per crown from three to more than 20 varied.

The young leaves stuck in cylindrical leaf sheaths which are densely covered with spines in all species. The leaf sheath then breaks up on both sides and are the stalked leaf and a clear visible ligule ( ligule ) free. This then forms back, but remnants remain visible in old leaves. The leaf sheath falls subsp all types with the exception of A. hirsuta. fosteriorum cleanly. The young leaves are dense with much branched leaf hairs ( trichomes ) covered.

The length of the leaf stems varies between a few centimeters to over one meter. Short petioles are notched above, whereas long are round without notch. The mean major axis of the Fiederblatts ( rachis ) is extended distally into a long filament ( filament), which then breaks off with time. Petioles and rachis are often littered with dense spines, with a few species but completely unarmed.

Any configuration of the leaflet at the leaf spindle varies greatly between species. It ranges from completely irregularly over in piles grouped towards paired opposite leaves.

During the growth of the lamina is cut twice from the top downward ( basipetal ), forming three irregular lobes. The midrib of the lower leaf surface is reinforced in all species with one or more spines. In some species, such as A. ulei, but also the upper leaf surface with rows of spines is busy. In A. minima, the spines can grow also from the side ribs.

Journal of Anatomy

The leaf blade is dorsiventral. The epidermis is only one cell layer thick. The cells are rhombohedral or spindle-shaped. The cell wall exterior is weak to strong cutinisiert. The anticlinal, ie perpendicular to the sheet surface standing, cell walls are thickened periodically. The thickened remember strung on a string beads. The stomata ( stomata ) are preferably abaxial, that is, on the underside of leaves. Rarely are these sunken or lifted.

The hypodermis, that is, the layer just beneath the epidermis only one cell, is also strong. The cells are twice as wide as those of the epidermis. The breath caverns beneath the stomata are surrounded by nine cells. The Chlorenchym is uniform and one to three cells thick. Raphids, bundles of needle-shaped calcium oxalate crystals are common. Fibers that are not associated with the vascular bundles are less than five microns in diameter and thickness without sclerenchyma. They lie in strands from two to four layers.

The leaf nerves run in the mesophyll, they consist of an outer layer of parenchyma cells, the larger nerves often not completely encloses before all things, and an inner one to seven cells thick layer of sclerenchyma. The phloem of the main nerve consists of two or four strands.

Inflorescences

Sting palm trees bloom more than once in life, so they are persistent ( pollakanth ). The flowers are monoecious getrenntgeschlechtig ( monoecious ).

The inflorescences are initially upright and can during anthesis, when the flowers open, tilt, until they hang down. During fruit ripening, they are often bent. In almost all species, one inflorescence per leaf axis developed in A. gelatinosa, however, there are often three. The bracts ( bracts ) are highly variable, they can be thickened and woody or thin and papery. They are often armed with spines, thin bracts often fall off, while maintaining woody.

The inflorescence is a piston-like in almost all species, but there simply branched. The inflorescence axis consists of a reinforced peduncle ( peduncle ) with a diameter of three to 50 millimeters and a rachis, the axes of the first order ( Rhachillae ) branch, which then sit on the flowers. In A. acaulis, A. spicata and A. macroloba, the inflorescence, however, is always in A. simplex mostly unbranched. At the pedicel sit flat, rounded and winged on the sides bracteoles ( Brakteolen ).

The flowers always sit in groups of three from two male flowers ( with androecium ) and female flowers ( with gynoecium ). Rarely found at the top of inflorescences ( distal) pairs in which the female flower is missing. In A. deltoidea and A. minima rarely result in groups of four, each consisting of two gender couples.

Male flowers

The male flowers are stalked or almost sessile. The perianth consists of three free, keeled and häutchenartigen sepals ( sepals ) and three free or fused at the base, fleshy petals ( petals ). Both are pointed. The flower color varies from cream to yellow -orange, or white to purple or violet. Often the flowers are still green before anthesis.

The sepals consist of only one to two layers of narrow cells. The petals are considerably thicker, in addition to the epidermis, they are composed of five or six layers of parenchyma cells with many Raphids and tannin cells and a layer of fibers that are not associated with the vascular bundles. They are powered from metaxylem by a single vascular bundle with two tracheae. The inner epidermis consists of a layer of large cells with a tough cytoplasm and large nuclei.

The six stamens are in two whorls of three. They are powered from metaxylem by a single vascular bundle with three to four tracheae. The stamens are fused at the base. You stand upright and are never longer than the petals. In diameter they have ten to 15 cells and are composed of parenchyma. The anthers open to the center of the flower out ( intrors ) or to the side ( latrors ). They are rounded and curved, or upright - at anthesis they tend often almost to the horizontal. The length varies between 0.3 and four millimeters and correlates with the size of the petals. The pollen sacs are rich in raphides. There are small, glandular stamp rudiments that are modified into nectaries.

Pollen

The pollen grains are monosulcat, that is, they have only one seed furrow. This is common in the southern half of the pollen grain ( meridionosulcat ). Rarely, there are three-armed seed furrows ( trichotomosulcat ). They are spherical to ellipsoid, rarely triangular. The longitudinal axis of between 20 and 30 micrometers long. The diameter varies from 20 to 30 microns.

The outer layer of pollen grains ( exine ) is wholly or partly covered with a tectum, a layer, the rod-shaped structures called the columellae covered. On the tectum often sit short or long spines, warts, or more or less severely overgrown delicate outgrowths. The Exinestruktur and ornamentation is made ​​a lot more diverse than in other Bactridinae genera.

Female flowers

The perianth of the female flower consists of three free, broadly keeled, thin, paper-like sepals and three curved or slightly keeled, fleshy petals. The latter are fused basally at half the length. Sepals have four to five cells strongly and comprise a layer of fibers that are not associated with the vascular bundles. The coloration of the female flowers seems to follow that of the male. In A. deltoidea however, they are in contrast to the male orange flowers, greenish.

Each flower contains six sterile stamens, staminodes. You have grown into a pointed lobed cup-shaped shell, which in turn is fused with the lower half of the sepals. The three globular carpels are fused ( synkarp ) and the stylus, whose length is approximately the stamens, wearing a three-piece scar. Just below the grain and on the opening of the central stylus channel between scars, small amounts of secreted nectar.

Fruit and seeds

The fruits of the palm trees are spiked round red seeded drupes, with a thick, hard, surrounding the seeds of woody core ( endocarp ) in most species. The endocarp is between 0.5 and two millimeters thick and brown or black color. It carries three distinct germ pores, each surrounded by a round, fibers lying in a star-shaped pattern. The mean pericarp ( mesocarp ) is fleshy and juicy. The diameter of the fruit varies from five to 25 millimeters, and is quite small in comparison to other Cocoeae.

Variations arise, for example, A. macroloba with ellipsoidal fruits, some species, such as A. grandis, form fruits with beak-shaped outgrowths. Also, the color may differ in some species of red from so A. grandis has dull green, and other species, such as A. verrucosa, white fruit. Purple fruits are found for example in A. hirsuta.

The seed coat is thin. The nutritive tissue ( endosperm) is white and homogeneous, often with an irregular cavity inside. The taste of the endosperm is sweet and reminiscent of coconut, the oil content varies widely within the genus and is, for example in A. horrida 37%, but in A. minima 65%. An essential component of the oil is lauric acid, in A. horrida almost 63%. The embryo is light brown in color, has an inverted conical shape and is 0.5 to one millimeter long. Its tip points to one of the three germ pores.

From the fruit of A. horrida a new stilbene compound was next iso- rhapontigenin, piceatannol and luteolin, Aiphenol isolated, which acts as an inhibitor of cyclooxygenase- reactions.

Dissemination

Sting palm trees are common in the Lesser Antilles, and from Venezuela to Bolivia along the Andes. A. hirsuta subsp. hirsuta reached Panama, otherwise lack the genus in Central America. The eastern boundary of the range is marked by the western border of the Amazon basin and reached in a very thin strip on the border with Peru Brazil. Alleged discoveries in Guyana and from the south of Venezuela could not be confirmed.

The diversity center of the genus, ie, the area with the greatest diversity of species, is located in western Colombia and Ecuador, a sub- center is found in northeastern Peru. The most widespread species is A. horrida, which is found from Trinidad to Bolivia, with a gap of central Colombia to central Peru. Many other species have only a small or very small area of ​​distribution.

In Tanzania in Africa exist neophyte occurrence of A. horrida, although spread wild, but not be classified as invasive.

Sting palm trees can live up to 2800 meters altitude, where other species are as widespread in the highlands in the lowlands. Also, the Aiphanes species have adapted to very different locations and it specialized exist both on very wet, and very dry conditions species. Even the plants in open areas behave differently than in dense forest areas. For example, while A. ulei, A. weberbaueri, A. parvifolia A. tricuspidata or can not survive in open terrain, fit, for example, A. erinacea or A. hirsuta to changing conditions and to make many short stems, and much more inflorescences.

Endangering

As with many species with highly specialized or endemic species, many species are endangered. The International Union for Conservation of Nature and Natural Resources (IUCN ) lists six of the 25 species in a category of threat on its Red List.

Three species are considered " high risk " ( endangered ) (A. grandis, A. and A. leiostachys verrucosa ) and another three as " endangered" ( vulnerable ) (A. chiribogensis, A. duquei, A. lindeniana ). In three species ( A. chiribogensis, A. grandis, A. verrucosa ) the situation is deteriorating constantly and there is a further deterioration to be feared. Especially A. grandis is in great danger because none of the remaining populations in Ecuador is located within a protected area. At least A. erinacea is also severely compromised, even if the species is not listed on the Red List.

For all species Habitat destruction is the main reason for the threat. Sites are mostly destroyed by deforestation and cultivation of the country. For A. erinacea has been shown that the type germinates only in pristine forests, but only slightly thinned forests but is received, this is probably true for other types of palm sting ..

Ecology

Most species bloom throughout the year and in a single population individuals can be found in all stages of budding, flowering and Fruktation the same time, often find themselves even in a single individual several stages at the same time. This is explained mainly from the relatively uniform climatic conditions in large parts of the range. However, there are also individual populations that evolve in parallel seasonal, such as a population of A. horrida in Canavi in Bolivia or populations at very high altitudes.

The anthesis takes at least 80 days, measured at A. chiribogensis and a new flowering occurs within approximately 25 days after the end of anthesis of the old flowering, measured at A. eggersii.

Pollination

The inflorescences are non-overlapping protandrous, that is, that the male flowers release the pollen at a time when the scars of the female flowers are not yet capable of assignment. An individual has only rarely more than an inflorescence at the same time - so self-pollination is prevented.

The sting palm species are pollinated by various insects ( entomophily ), with some species also wind pollination ( anemophily ) plays a role. Finn Borchsenius examined the pollination of A. chiribogensis, A. and A. Eggersi erinaceae in western Ecuador. In the male flowers of A. eggersii he found many larvae of small butterflies ( Microlepidoptera ), but he closed on pollination by bees ( Apiformes ) and wind. The flowers of A. erinacea are hundreds of flies, especially fruit flies ( Drosophilidae ), hoverflies (Syrphidae ), biting midges ( Ceratopogonidae ) and leaf beetles ( Chrysomelidae ) visits, which probably also assume the pollination. Bees he did not observe here. The flowers of A. chiribogensis be visited by significantly fewer insects. Here you will find fruit flies, fungus gnats ( Mycetophilidae ), fungus gnats ( Sciaridae ), gall midges ( Cecidomyiidae ), midges and small butterflies. Bees or hoverflies are missing.

The flowers of A. grandis and A. minima smell sweet to attract insects. An analysis of the scent of the male flower of A. minima yielded 15 ingredients. The main components are pentadecane ( 75.5 %), tetradecane ( 3.9%), 1,3,7- Nonatrien linalool ( 1.2%) and dihydro- β -ionone ( 1.2%).

A. horrida is of stingless bees ( Meliponini ) and Schnabelkerfen ( Hemiptera ) visited the pollination takes place by bees. Beetles ( Nitidulidae ) and weevils ( Curculionidae ) are found exclusively in male flowers.

Overall, probably the species with large white or yellow flowers and linear anthers mainly by bees, and the species with small, mostly white to purple flowers with small, oval anthers pollinated mainly by flies.

Seed dispersal

The ripe fruits of A. horrida are eaten by squirrels (Sciurus ), are able to climb the trunk despite the many spines. The fruits are rich in energy, contain many vitamins and are probably eager consumed by many other animals. The spines of the whole plant in total, protection against herbivores and animals that want to climb the trunks to get to the fruit. The bright red fruit of A. horrida are also eaten by the fat Schwalm ( Steatornis caripensis ), which she swallowed as a whole and the seeds spread ( Endochorie ).

Use

The fruits of A. horrida are offered under the name Corozo or Mararay in many markets in Colombia and can even be found in supermarkets in Medellin. They are eaten raw. Candied fruits are very popular as candy in the Andes. A. horrida is the only species of the genus that is cultivated for its fruit, the fruit of other species are collected only in nature.

The fruits of A. linearis are also tasty and can be eaten in Colombia. The fruit kernels of A. minima are edible, and are traded as nuts.

Despite the spines are occasionally used as a specimen plant in gardens A. horrida and A. minima. In the Botanical Gardens, the two species are widespread. The wood of palms sting has no economic significance.

Botanical history and etymology

Specimens of the genus Aiphanes were first collected by Charles Plumier, a French missionary and botanist who took three trips to the Caribbean 1689-1695. He made drawings and described two types, which he fructu Corallino, minor called Palma dactylifera, aculeata, fructu Corallino, major and Palma dactylifera, aculeata. Both were copies of today's species A. minima. The same type was described again in 1763 by Nikolaus Joseph von Jacquin as Palma grigri martinicensibus.

1779 José Mutis made ​​a very accurate description of the type, which is now known as A. lindeniana. In 1791, the German gardener Joseph described the seeds of A. minima in his book " De fructibus et seminibus plantarum " under the name Bactris minima - minimal order is the oldest recognized species epithet Aiphanes a - kind.

The genus name Aiphanes was first used in 1801 in a lecture at the Royal Academy of Sciences in Berlin by Karl Ludwig Willdenow. The name comes from the ancient Greek αεί, ai ( = always) and φανερός, phaneros ( = obvious, visible, conspicuous ) together. Ironically, sting palms usually difficult to identify in dense vegetation and were rarely collected for this reason in herbaria. Probably the name refers more to the eye-catching appearance of the plants.

Willdenow described only one species of the genus A. aculeata, which is a synonym of A. horrida today. The holotypische specimen had been collected by Franz Meyer in Brede Caucagua, Venezuela. Brede Meyer went to Schonbrunn and took either the holotype or seeds of this specimen with. 1809 Joseph Franz von Jacquin described the same holotype or a streaked copy under the name Caryota horrida - today the Epipheton horrida is the recognized as valid.

Between 1794 and 1816 several palm trees have been described under the generic name Martinezia - the genus, however, was inconsistent and was synonymized in 1847 by Carl Friedrich Philipp von Martius with Aiphanes. Since Martinezia was the older name, the generic name Aiphanes was not used until 1932. However, the genus Martinezia contained many palm trees that are not to be equated with the thorn trees. Carl burret led so again in 1932 the name Aiphanes one. The majority of the species from Martinezia was to the genus Euterpe asked why Martinezia today is synonymous to Euterpe. Most of the species described by burret were collected by Wilhelm Kalb Reyer, who had traveled north Colombia 1877-1881 and an extensive collection of palm trees brought from the 69 new palm species have been described.

Between 1932 and 1996, 15 more sting palm species have been described, which is the number of species increased to 47. Published in 1996 Finn Borchsenius and Rodrigo Bernal an extensive monograph on the genus in which the number of species was reduced to 22. Since then, however, three new species have been described.

System

Outer systematics

John Dransfield and colleagues place the genus within the family Arecaceae Aiphanes in the subfamily Arecoideae, Tribe Cocoseae, subtribe Bactridinae. At this still include the genera Acrocomia, Astrocaryum, Desmoncus and Bactris. Within the subtribe, the relationships are not clear, various works came to different results. A common feature of the genera are spines on at least parts of the plants and the neotropical distribution area.

In addition to the spiny palms of these tribes, but there are also other genres bestachelter palm trees not only in the Neotropics, these are with the genre Aiphanes but not closely related.

A molecular genetic study of 2002 revealed the following cladogram, which is one of the several proposed relationships within the subtribe Bactridinae.

Acrocomia

Astrocaryum

Aiphanes

Desmoncus

Bactris

Inside systematics

Today 25 recognized species belong to the genus. It is unclear, the position of Aiphanes leiospatha burret, the species is listed as " Unplaced Name".

The genus Aiphanes is a morphologically well-defined unit. Their position as monophyletic group is therefore not in doubt.

Carl burret divided the genus into two subgenera 1992 Macroanthera and Brachyanthera. He distinguished this primarily on the basis of morphological characteristics of the flowers, especially the length of the anthers and the position of the inflorescences. These features are so vague that an unambiguous assignment is not possible. However, the three species in the subgenus Macroanthera seem to be closely related, but it is not clear whether this group is monophyletic. Today, the division is usually not followed - in the absence of a newer subdivision it is still used here.

The species of the genus are:

Subgenus Macroanthera burret

  • A. eggersii burret
  • A. horrida ( Jacq. ) burret
  • A. minima ( Gaertn. ) burret

Subgenus Brachyanthera burret

  • A. deltoidea burret
  • A. erinacea ( H.Karst. ) H.Wendl.
  • A. hirsuta burret A. hirsuta subsp fosteriorum ( H.E. Moore) Borch. & R. Bernal
  • A. hirsuta hirsuta subsp burret
  • A. hirsuta subsp intermedia Borch. & R. Bernal
  • A. hirsuta subsp kalbreyeri ( burret ) Borch. & R. Bernal

Not assigned

  • A. acaulis Galeano & Bernal R.
  • A. bicornis Cerón C. & R. Bernal
  • A. chiribogensis Borch. & Balslev
  • A. duquei burret
  • A. gelatinosa H.E. Moore
  • A. graminifolia Galeano & Bernal R.
  • A. grandis Borch. & Balslev
  • A. linearis burret
  • A. spicata Borch. & R. Bernal
  • A. stergiosii M. Niño, Dorr & F.W. Stauffer
  • A. tricuspidata Borch. , R. Bernal & M. Ruiz
  • A. verrucosa Borch. & Balslev
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