Rhapis robusta

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Rhapis (RAH-pis)
robusta (roh-BOOS-tah)
20160113 162859.jpg.f96dd709b2e8b816763504a85126905c.jpg
Cutler Bay, FL. Photo by Andrew Street.
Scientific Classification
Genus: Rhapis (RAH-pis)
Species:
robusta (roh-BOOS-tah)
Synonyms
None set.
Native Continent
Asia
Asia.gif
Morphology
Habit: Clustering
Leaf type: Costapalmate
Culture
Survivability index
Common names
Robust-caned bamboo palm, Robust lady palm. FRENCH: Palmier nain cespiteux, Rhapis nain du Kwangsi. CHINESE: Cu zong zhu.

Habitat and Distribution

China Southeast. South China, Guangxi. Lowland forests on slopes of limestone
Cutler Bay, FL. From left to right, laosensis(very bottom left), robusta, humilis, multifida. Photo by Andrew Street.
mountains; 300-1000 m. Guangxi (Vietnam).

Description

Stem height not recorded, with sheaths to 11 mm in diam., without to 6 mm. Leaf sheath fibers close together with outer coarse fibers, obscuring finer inner ones, producing a diagonal-lined mesh, ligule remaining intact at maturity; petiole to 1.2 mm wide, smooth; blade, with conspicuous palman, segments 4, folds 17–19, the longest to 218 mm, broad, sides curved, tapering at base and apex, apices oblique, with shallow secondary splitting, primary splits to within 16–37 mm of the blade base. Inflorescence, male unavailable, female branching to 2 orders; prophyll unavailable, rachis bracts 2, sometimes with a distal incomplete rachis bract, tubular, not overlapping the base of the next bract, relatively thin (papery), reddish brown, darker at the base, glabrous, tightly sheathing the rachis; rachis overall length to 220 mm, narrow, 2 mm in diam., rachillae few, narrow to 0.5 mm in diam., occasionally with sparse rusty tomentum. Flowers, male unavailable, female small to 1.8 × 1 mm; corolla tightly closed with a long receptacular-stalk to 0.9 mm; carpel to 1 mm long. Fruit unavailable. (L. Hastings. 2003)/Palmweb. Editing by edric.

Only one specimen of this species was available for study; more specimens are needed in order to gain a more complete picture. A notable characteristic of this specimen is that the apices of the bracts do not overlap with the base of the bract distal to them. The height was not recorded on the specimen label, but it is likely from the other measurements taken that this species is smaller than the other species and the specimen seen was more slender than any of the other specimens of the genus. According to the specimen label, the flowers are light green and the fruit is green. (L. Hastings. 2003)/Palmweb.

Stems clustered, rhizomatous, forming colonies, to 1.5 m tall, to 0.6 cm in diam., covered with persistent, fibrous leaf sheaths. Leaf sheaths with coarse, black or brown fibers producing a diagonal mesh; ligules persistent; blades not split to base, divided into 3-6 segments, these with curved sides and ± pointed apices, to 22 × 2-3 cm. Inflorescences borne among leaves, branched to 2 orders; bracts tubular, sheathing, not or scarcely overlapping; rachis to 22 cm; rachillae 2.5-5 cm, ± glabrous; male flowers not known; female flowers about 2 mm. Fruits developing from 1 carpel, color not known, ellipsoid, to 0.5 cm in diam., borne on short stalks. (efloras.org)

Culture

Cold Hardiness Zone: 9a

Comments and Curiosities

Rhapis robusta [cūzōngzhú] Another frustrating example: Rhapis robusta. Henderson 2009: »Stems … to 1.5 m tall and 0.6 cm diameter. … blades … divided into 3-6 leaflets.« Ministry of Forestry/China [smbk.forestry.gov.cn]: Stems 2-2.5 tall and ca. 2 cm diameter, blades with 5(6-7) leaflets.

(1) 3-6 [5-7*] leaflets (my Rhapis 2004: to 11) (* A photo of a “Rh. robusta” on that website shows a palm with over 10 leaflets.)

(2) blades not split to the base

(3) pointed apices of leaflets

(4) petiole 1.2 mm wide (my Rh. 2004: to 3.5 mm)

(5) ligules persistent

(6) stem with sheaths to 1.2 [2] cm diameter [2-2.5 m tall] (my Rh. 2004: to 1.7 cm diameter)

(7) stem without sheaths to 0.6 cm diameter

Notations by Research Work Editor palMeir.

What many of us learned while attending the biennial in Thailand a few years back was that many plants in our collections are misidentified. So unless you have flowering plants that you can key out without other species growing nearby, it's extremely difficult to be sure on what you have. Noong Nooch Gardens has a world class collection of Rhapis spp. (Jeff Searle, Searle Brothers Nursery Florida)


External Links

References

Phonetic spelling of Latin names by edric.

Special thanks to Geoff Stein, (Palmbob) for his hundreds of photos.

Special thanks to Palmweb.org, Dr. John Dransfield, Dr. Bill Baker & team, for their volumes of information and photos.

Glossary of Palm Terms; Based on the glossary in Dransfield, J., N.W. Uhl, C.B. Asmussen-Lange, W.J. Baker, M.M. Harley & C.E. Lewis. 2008. Genera Palmarum - Evolution and Classification of the Palms. Royal Botanic Gardens, Kew. All images copyright of the artists and photographers (see images for credits).

Hastings, L.2003. A Revision of Rhapis, the Lady Palms. Palms 47(2) 62-78.


Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.

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