Rhapis

Rhapis excelsa

Rhapis is a Native to Southeast Asia genus of the palm family. The genus is characterized by leaves, their division into segments between the folds, not like palm trees common along the folds. Several species are used as ornamental plants.

Features

The representatives are sleek, multi-stemmed fan palms. They are dioecious or rarely polygamous. The stem is tubular, erect and covered with leaf sheaths.

The leaves are fan folded and induplicat. The petiole is long and slender, the edge smooth or slightly rough. The Hastula on the top is small and triangular, one abaxial Hastula missing. The adult leaf blade is bare and divided between the folds into segments consisting of several ribs. The larger incisions extend to one-third of the blade radius or until completely to the center. The tips of the segments are more easily cut.

The inflorescence is between the leaves, male, female and hermaphrodite inflorescences are similar to each other. An inflorescence is branched from one to three times. The cover page is Roehrig and zweikielig. It tears open along the abaxial midline. The inflorescence stem is usually completely enclosed in the leaf sheath, bracts absent in him. The inflorescence axis is longer than the peduncle. On the axis are one to three, rarely four large, einkielige bracts with sheath carrying the lateral axes of the first order. The flower-bearing axes ( Rachillae ) are soft, spreading, sometimes sometimes crowded. At ihne are in a spiral arrangement of individual flowers, rare flowers are in pairs in the axils of minute bracts.

There are male, female and hermaphrodite flowers, which resemble each other. The calyx is cup-shaped, three-lobed, sometimes with irregular lobes. The crown is fleshy, Roehrig and three-lobed, usually with a stem-like base, which consists of receptaculum and crown. There are six stamens or staminodes in two circles. In the male flowers, the filaments are fused almost along the entire length of the corolla tube with this and only at the tips free. The anthers are basifix, short and roundish. The pollen is elliptical, monsulcat with fine reticulate surface. The stamp rudiment is very small. The female flowers have six staminodes. The three carpels are wedge-shaped, each has a short stylus with a cylindrical scar. Each carpel contains an ovule. This basal seat, is hemanatrop and contributes to the base a fleshy aril.

The fruit develops from a single carpel, rarely of two or three. The fruit is stalked, at the top of the fruit is a residual scar. The exocarp is papillose, the mesocarp is fibrous, endocarp thin. The seed has a short lateral raphe. The endosperm is homogeneous.

The chromosome number is 2n = 36 There are also tetraploid taxa with 4n = 72

Dissemination and locations

Rhapis comes from southern China to the south over Indochina to the Thai peninsula. One species is found in the northernmost part of Sumatra. The representatives grow in the understory of tropical evergreen forests. Rhapis subtilis and other species appear to be restricted to sandstone hills.

System

The genus Rhapis is placed in the subfamily Coryphoideae, Tribe Trachycarpeae, subtribe Rhapidinae within the family Arecaceae. The monophyly of the genus has not yet been investigated. Their sister group is likely to be Guihaia.

In the World Checklist of Selected Plant Families of the Royal Botanic Gardens, Kew, the following types are recognized:

• Rhapis cochinchinensis
• Rhapis excelsa
• Rhapis gracilis
• Rhapis humilis
• Rhapis micrantha
• Rhapis multifida
• Rhapis puhuongensis
• Rhapis robusta
• Rhapis siamensis
• Rhapis subtilis
• Rhapis vidalii

Use

Several species are used as ornamental plants. Already Engelbert Kaempfer described his journey 1690-92 the cultivation of Rhapis excelsa in Japan, where the species is absent. The first plants arrived by James Gordon in 1774 to Europe. Rhapis excelsa, humilis and Rhapis Rhapis subtilis are very common in the United States recognized as ornamental plants. In Japan there are many dwarf and variegated varieties of Rhapis excelsa and humilis Rhapis. Other species were placed in culture since the 1960s.

The logs are processed into sticks and umbrellas.

Documents

• John Dransfield, Natalie W. Uhl, Conny B. Asmussen, William J. Baker, Madeline M. Harley, Carl E. Lewis: Genera palmarum. The Evolution and Classification of Palms. Second edition, Royal Botanic Gardens, Kew 2008, ISBN 978-1-84246-182-2, pp. 226ff.
• Laura H. Hastings: A revision of Rhapis, the Lady Palms. Palms, Volume 47, 2003, pp. 62-78.