Ixerba brexioides ist eine immergrüne Baumart auf Neuseeland, die alleine die Pflanzen-Gattung der Ixerba innerhalb der Familie Strasburgeriaceae bildet. Auf Neuseeland wird die Art „Tāwhiri“ oder „Tawari“ genannt, die Blüten „whakou“.
Es ist ein immergrüner Baum mit ausladender Krone, der bis zu zehn Meter hoch wird. Der Stamm erreicht einen Durchmesser von 0,2 bis 0,4 Metern. Die Borke ist dunkel- bis grau-braun. Die Zweige, Blätter und Blütenstände sind leicht behaart, wenn jung.
Die Blätter stehen pseudoquirlförmig. Sie sind nebenblattlos. Die Blattstiele sind zwei Zentimeter lang und fleischig. Die Blätter sind an der Oberseite gelbgrün bis dunkelgrün, an der Unterseite immer heller. Junge Blätter sind oft rötlich. Sie sind etwas fleischig, ausgesprochen ledrig, 60 bis 160 Millimeter lang und 10 bis 40 Millimeter breit, lanzettlich bis elliptisch mit einem spitzen Apex. Der Blattrand ist deutlich und grob gezähnt. An der Spitze jeden Zahnes sitzt eine kleine Drüse.
Die Blütenstände stehen terminal, bestehen aus fünf bis zehn Blüten, die eine schirmförmige Ähre bilden. Die Blüten sind weiß, relativ groß (25 bis 35 Millimeter Durchmesser) mit je fünf Kelch- und Kronblättern, zehn Staubblättern mit dicken Konnektiven. Der Pollen ist 4- bis 5-colporat. Der Fruchtknoten ist auffällig, besteht aus fünf verwachsenen Fruchtblättern und geht allmählich in den Griffel über. Der Griffel ist stark gefurcht und an der Spitze spiralig gedreht. An der Basis des Fruchtknotens sitzt ein gelapptes Nektarium. Die Gefäßbündel im Blütenboden sind dicht zusammengedrängt. Blütezeit ist Oktober und November.
In der zugespitzten Kapselfrucht befinden sich wenige glänzend schwarze Samen mit einem auffälligen orange-roten Arillus. Fruchtreife ist von November bis Jänner. Die Verbreitung der Samen erfolgt möglicherweise durch Tauben.[1]
Der Art fehlen nicht-hydrolysierbare Tannine. Die Chromosomenzahl ist n=25.
Ixerba brexioides ist auf der Nordinsel von Neuseeland endemisch. Das Areal ist beschränkt auf den Norden der Nordinsel etwa von Waitomo, Paeroa Range und Te Urewera nach Norden bis zu den Hügeln südlich von Kaitaia.
Der Baum wächst in Kauri-Wäldern und montanen Nebelwäldern. Er bevorzugt schattige und geschützte Stellen, oft nahe Fließgewässern und auf ständig feuchtem Boden. Die Art ist eher selten und tritt nur an manchen Stellen in größeren Zahlen auf. Sie ist aber nicht gefährdet.
Die Art kann nur schwer in Kultur genommen werden. Es wird vermutet, dass sie eine Mykorrhiza zum Wachsen benötigt. Wenn sie zusammen mit Griselinia littoralis gepflanzt wird, soll sie gut wachsen.[2]
Innerhalb der Crossosomatales ist Ixerba das Schwestertaxon von Strasburgeria. Beide Gruppen haben folgende gemeinsame Merkmale: zumindest in den Blüten Zellen mit verdickten verschleimten inneren Tangentialwänden; nadelförmige Kristalle; spiralige Blätter mit drüsig-gezähntem Rand; große Blüten mit spiraligem Kelch; flache Filamente; Antheren über drei Millimeter lang; Fruchtblätter sitzend, epitrop mit langem hohlem Griffel, der an der Frucht erhalten bleibt; Chromosomen-Grundzahl von 25.
Cronquist hatte 1981 Ixerba in die Grossulariaceae gestellt, Airy Shaw in die Brexiaceae und Tachtadschjan 1997 in die Rosidae-Brexiales. Die Angiosperm Phylogeny Group stellt die Gattung seit 2009 zusammen mit Strasburgeria in die Familie Strasburgeriaceae.[3]
Ixerba brexioides ist eine immergrüne Baumart auf Neuseeland, die alleine die Pflanzen-Gattung der Ixerba innerhalb der Familie Strasburgeriaceae bildet. Auf Neuseeland wird die Art „Tāwhiri“ oder „Tawari“ genannt, die Blüten „whakou“.
Ixerba brexioides, the sole species in the genus Ixerba, is a bushy tree with thick, narrow, serrated, dark green leaves and panicles of white flowers with a green heart. The fruit is a green capsule that splits open to reveal the black seeds partly covered with a fleshy scarlet aril against the white inside of the fruit. Ixerba is an endemic of the northern half of the North Island of New Zealand. Common names used in New Zealand are tawari (Māori: tāwari) for the tree and whakou when in flower.[1] It is assigned to the family Strasburgeriaceae.[2]
Tawari is a small tree of up to 10 m high with a spreading crown. The trunk is usually between 2–4 dm in diameter, and covered by a dark to grayish brown bark. Young branches have few flat-lying pale unicellular T-hairs, while the peduncles, pedicels, sepals and petals are thickly covered in such hairs, giving them a felty look. The leaves are alternately positioned along the stem and often almost create a whorl at the end of a growth period, with the bud at the end covered in stout triangular scales. These scales have entire margins fringed with simple single celled hairs. The first leaves to appear when growth recommences are an intermediate series between schales and full leaves. Stipules at the base of the leaf stem are absent. The leaf stalk is stout, fleshy and about 2 cm long. The somewhat fleshy and distinctly leathery simple leaf blades are yellowish to dark green on top and pale green beneath and measure 6-16 × 1–4 cm, are lanceolate to elliptic in shape, while the widest point may be at or beyond midlength, with a pointy tip, and the edges are coarsely serrated. A small gland is present at the tip of each tooth. Young leaves are often reddish and have rolled-in margins. Leaves on young shoots may be relatively narrower. Old leaves discolor to orange or red.
Flower buds are formed in March and April and these open from October to the end of December varying according to location and altitude. The inflorescence sits at the end of the branches in an umbel-like panicle that consists of five to fifteen flowers. Each flower is hermaphrodite, starsymmetric, 21⁄2—31⁄2 cm in diameter and produces copious amounts of nectar, but apparently does not emit a scent. The five sepals are broadly oval, covered in downy hairs and 5–6 mm long. The five petals are overlapping in the bud, white, felty, spoon-shaped with a narrow base (or claw). The claw is 11⁄2-2 cm long and is inserted on a 5-lobed disc. The five stamens extend well beyond the corolla and alternate with the five lobes of the disc at the centre of the flower. The filaments are very long and white. The anthers are connected to the filaments midlength and open in lengthwise slits towards the middle of the flower. Pollen grains have five slits. The nectar is produced by the ledges of the disc, just above the petal implant. The five styles that rise from the disc are sometimes free from each other at their based and are twisting and fused higher up.
The fruit is a leathery capsule, broadly oval in shape. These contain five spaces that split open outwards from the base of the style when the fruit is ripe by April. Each space contains two shiny black seeds that are shaped like a slightly curved tear drop of 6×3 mm, and are partly covered by a conspicuous scarlet aril, both of which starkly contrast with the horny white inside of the fruit (or mericarp). Aborted seeds are greyish. The embryo is green. Ixerba has fifty chromosomes (2n = 50).[2][3][4][5]
Ixerba has been assigned to different families over time. Traditionally it was regarded related to Roussea and Brexia and has been combined with them in the Brexiaceae. These three have been placed in different other famililies, such as the Escalloniaceae, but doubt remained about their proper placement. After genetic analysis showed that Ixerba was not very much related to either Roussea or Brexia, it was placed in the monogeneric family Ixerbaceae. However, further testing revealed that Ixerba was closely related to the New Caledonian genus Strasburgeria and it was assigned to the Strasburgeriaceae by the APG III in 2009.[2]
Fossil remains of Ixerba have been found from the Middle Miocene.[5]
Recent phylogenetic analysis resulted in the following tree.[6]
family StrasburgeriaceaeIxerba
The genus name Ixerba is an anagram of Brexia, a treelet from Madagascar and the coast of East Africa, to which it bears a superficial likeness. The species epithet brexioides means "like Brexia".[2]
Tawari is a species endemic to the North Island of New Zealand, roughly north of a line crossing Taupo. It is said to be widespread from about Kaitaia south to Waitomo, and Te Urewera, including the Tutamoe Ranges, the Waitākere Ranges, Waipoua Forest, Te Moehau on the Coromandel Peninsula, higher elevations on the Barrier Islands and elsewhere around the Bay of Plenty.[2][4]
Tawari can often be found together with the New Zealand kauri Agathis australis in the understory of the lowland rain forest. It is common in cloud forest up to 700 m too. The species has a preference for shaded or sheltered locations, often in permanently damp soil and near streams. It is locally abundant but mostly individuals are far between. It is common in regenerating forests along with tawheowheo Quintinia serrata.
Tawari has a mass flowering strategy, attracting a range of visitors with the abundant nectar it produces. Each flower produces on average 18 μl of nectar with an average concentration of 20% brix. Pollination is mainly by birds, however in modified forest where birds a few in number, flower visitation is most frequently by large flies and moths, followed by honey bees, bumblebees, native bees, wasps and beetles.[1] Floral morphology, such as its wide spreading anthers, suggest adaptation to pollination by birds.[2][4][7] Seeds capsules develop between January and April each year, and dehisce to reveal up to ten glossy, purple-black seeds that are partly covered by an orange fleshy aril. Seeds are primarily dispersed by birds, with reports including kererū, pōpokotea, hihi, and kākā.[1]
Tawari is a rich source of nectar, which is often so abundant that bees produce monofloral honey, that is the honey is chiefly made of nectar from tawari flowers. Tawari honey is regularly for sale from food shops in New Zealand. The nectar contains a lot of fructose and much water. The honey may be thin as a consequence, but nonetheless crystallizes quickly. The honey has a light colour and tastes a bit like butterscotch. It contains relatively few pollen, and if at least 20% of the pollen is tawari, it can be marketed as tawari honey.[2][7][8] Bark can produce a black dye that is known to be used on flax.[9] Māori people traditionally used the flowers to make necklaces and other adornments to be worn at festivities.[7]
Tawari is known to be very difficult to grow in gardens. It needs a sheltered location, humus-rich soil and good drainage, but the soil should never dry out. The species probably depends on a mycorrhiza, and if planted next to Kapuka Griselinia littoralis, tawari does much better.[2][10]
Photo series illustrating many details of the anatomy
Ixerba brexioides, the sole species in the genus Ixerba, is a bushy tree with thick, narrow, serrated, dark green leaves and panicles of white flowers with a green heart. The fruit is a green capsule that splits open to reveal the black seeds partly covered with a fleshy scarlet aril against the white inside of the fruit. Ixerba is an endemic of the northern half of the North Island of New Zealand. Common names used in New Zealand are tawari (Māori: tāwari) for the tree and whakou when in flower. It is assigned to the family Strasburgeriaceae.
Ixerba, monotipski biljni rod u porodici Strasburgeriaceae, red Crossosomatales. Jedina vrsta I. brexioides od Maora nazivana tāwari) endem je na novozelandskom otoku Sjeverni otok
I. brexioides je drvo koje raste po nizinskim i niskim šumama platoa Mamaku. Može narasti do 10 metara visine[1], a kada procvjeta u kasno proljeće do sredine ljeta nazivaju ga whakou. Sjemenske kapsule, svaka sa pet crnih sjemenki, formiraju se do rane jeseni.
I. brexioides
Ixerba, monotipski biljni rod u porodici Strasburgeriaceae, red Crossosomatales. Jedina vrsta I. brexioides od Maora nazivana tāwari) endem je na novozelandskom otoku Sjeverni otok
I. brexioides je drvo koje raste po nizinskim i niskim šumama platoa Mamaku. Može narasti do 10 metara visine, a kada procvjeta u kasno proljeće do sredine ljeta nazivaju ga whakou. Sjemenske kapsule, svaka sa pet crnih sjemenki, formiraju se do rane jeseni.
I. brexioides
Tawari (Ixerba brexioides) er eit dekkfrøblada blomeberande tre, det einaste medlemet av den einaste karplantefamilien som er endemisk (stadeigen) på New Zealand. Det finst berre på Nordøya, mellom Waitomo og Kaitaia, og er brukt i produksjon av honning. Treet veks ofte i område med kauritre.
Treet kan veksa seg opp til 15 meter høgt med ein stamme frå 10 til 20 cm i diameter. Det har vakre, kvite blomar, og blømer frå oktober til sist i desember, vanlegvis seinare di høgare og lenger sør det veks[1].
Tawari (Ixerba brexioides) er eit dekkfrøblada blomeberande tre, det einaste medlemet av den einaste karplantefamilien som er endemisk (stadeigen) på New Zealand. Det finst berre på Nordøya, mellom Waitomo og Kaitaia, og er brukt i produksjon av honning. Treet veks ofte i område med kauritre.
Ixerbaceae é uma família de plantas angiospérmicas (plantas com flor - divisão Magnoliophyta), pertencente à ordem Crossosomatales. O grupo inclui apenas uma espécie - Ixerba brexioides, uma árvore endémica da Nova Zelândia.
Ixerbaceae é uma família de plantas angiospérmicas (plantas com flor - divisão Magnoliophyta), pertencente à ordem Crossosomatales. O grupo inclui apenas uma espécie - Ixerba brexioides, uma árvore endémica da Nova Zelândia.
Tawari trong ngôp ngữ New Zealand, tên khoa học Ixerba brexioides, là một loài thực vật có hoa trong họ Strasburgeriaceae. Loài này được A.Cunn. miêu tả khoa học đầu tiên năm 1839.[1]
Đây là loài duy nhất trong chi Ixerba, cũng như họ Ixerbaceae. Chúng chỉ được tìm thấy trên đảo North, giữa Waitomo và Kaitaia. Loài này được sử dụng để sản xuất một loại mật ong đặc biệt.
Hệ thống APG III năm 2009 không công nhận họ Ixerbaceae mà gộp nó trong họ Strasburgeriaceae.
Tawari trong ngôp ngữ New Zealand, tên khoa học Ixerba brexioides, là một loài thực vật có hoa trong họ Strasburgeriaceae. Loài này được A.Cunn. miêu tả khoa học đầu tiên năm 1839.
Đây là loài duy nhất trong chi Ixerba, cũng như họ Ixerbaceae. Chúng chỉ được tìm thấy trên đảo North, giữa Waitomo và Kaitaia. Loài này được sử dụng để sản xuất một loại mật ong đặc biệt.
Hệ thống APG III năm 2009 không công nhận họ Ixerbaceae mà gộp nó trong họ Strasburgeriaceae.
Ixerba A.Cunn. (1839)
Единственный вид
Ixerba brexioides — единственный вид растений из рода Ixerba семейства Страсбургериевые (Strasburgeriaceae). Эндемик Новой Зеландии. Маорийское название растения — tāwari («тавари»).
До 2009 года род Ixerba выделялся в составе монотипного семейства Иксербовые (Ixerbaceae), которое было единственным новозеландским эндемичных семейством сосудистых растений. В 2009 году APG (группа филогении покрытосеменных) включило это семейство в состав новокаледонского семейства Страсбургериевые (Strasburgeriaceae)[2][3].
Произрастает на территории острова Северный от округа Уаитомо и Те-Уревера на севере до горных хребтов, расположенных к югу от Каитаиа. Встречается в лесах с преобладанием дерева каури, а также в горных лесах. Предпочитает тенистые, постоянно увлажнённые места, расположенные недалеко от ручьёв[2][4].
Ixerba brexioides — небольшое вечнозелёное дерево высотой до 15 м с раскидистой кроной[5]. Диаметр ствола — 0,2—0,4 м. Кора тёмно-коричневая или серо-коричневая[2].
Ветки, листья и соцветия покрыты в молодом возрасте пушком. Расположение листов супротивное или мутовчатое[5]. Черешок листа плотный, мясистый, длиной 20 мм. Листья в верхней части от жёлто-зелёного до тёмно-зелёного цвета, снизу более бледные, мясистые, кожистые, длиной 60—160 мм, шириной 10—40 мм, ланцетовидные или эллиптические по форме (иногда обратноланцетовидные). Кончик листа острый или слегка заострённый. Молодые листья часто красноватые, линейно-ланцетовидные[2].
Соцветие состоит из 5—10 цветущих метёлок. Цветение, как правило, длится с октября по ноябрь. Цветки симметричные, совершенные, диаметром 25—35 мм, с большим количеством нектара[5]. Чашелистик широкий, овальный, длиной 5—6 мм. Лепестки белые, длиной 15—20 мм. Тычинок 5. Семенная коробочка кожистая, яйцевидная, открывается посредине створок[6]. Семена ярко-чёрные, с ярко-оранжевым мясистым образованием на нижней стороне, который образуется из семяносца[4]. Длина семени — 5 мм[2].
Ixerba brexioides, известная среди представителей новозеландских маори под названием тавари, не представляет собой какой-либо экономической ценности. Однако нектар растения используется при производстве мёда[6].
Ixerba brexioides — единственный вид растений из рода Ixerba семейства Страсбургериевые (Strasburgeriaceae). Эндемик Новой Зеландии. Маорийское название растения — tāwari («тавари»).
西兰木科又名龙柱花科，只有1属1种，是单种科，只生长在新西兰的北岛，是当地的特有种。
本科植物是常绿乔木，单叶，无托叶；花相当大，花瓣5，雄蕊10，雌蕊花柱螺旋状扭转；果实为蒴果，内含黑色种子。
1981年的克朗奎斯特分类法将其列在茶藨子科中，属于蔷薇目，1998年根据基因亲缘关系分类的APG 分类法认为应该单独分出一个科，但无法分在任何目中，直接放到蔷薇分支之下， 2003年经过修订的APG II 分类法维持原分类，但2006年5月7日新修订的结果是放到缨子木目中。
西兰木科又名龙柱花科，只有1属1种，是单种科，只生长在新西兰的北岛，是当地的特有种。
本科植物是常绿乔木，单叶，无托叶；花相当大，花瓣5，雄蕊10，雌蕊花柱螺旋状扭转；果实为蒴果，内含黑色种子。
1981年的克朗奎斯特分类法将其列在茶藨子科中，属于蔷薇目，1998年根据基因亲缘关系分类的APG 分类法认为应该单独分出一个科，但无法分在任何目中，直接放到蔷薇分支之下， 2003年经过修订的APG II 分类法维持原分类，但2006年5月7日新修订的结果是放到缨子木目中。
타와리(Ixerba brexioides)는 익서바속(Ixerba)에 속하는 유일종의 속씨식물로, 뉴질랜드에서만 자생하는 관다발식물이다. 익서바과(Ixerbaceae)의 단일 종이다. 와이토모와 카이타이아 사이의 북아일랜드에서만 발견된다. 유기농 꿀을 만드는 데 사용된다.
APG 분류 체계와 APG II 분류 체계에서는 익서바과(Ixerbaceae)의 유일속, 유일종으로 분류했었으나, APG III 분류 체계에서는 크로소소마목에 속하는 스트라스부르게리아과 식물로 분류하고 있다.
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