Ravenea krociana

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Ravenea (rah-vehn-EH-ah)
krociana (kro-see-AHN-ah)
Ravenea-krociana.jpg
Photo: trebrown.com
Scientific Classification
Genus: Ravenea (rah-vehn-EH-ah)
Species:
krociana (kro-see-AHN-ah)
Synonyms
None set.
Native Continent
Africa
Africa.gif
Morphology
Habit: SAolitary
Leaf type: Pinnate
Culture
Survivability index
Common names
Vakakabe (Antanosy).

Habitat and Distribution

Endemic to Southeast Madagascar: Endemic to the submontane zone of southeast
Andohahela, Madagascar. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb.
Madagascar occurring between Andohahela and Ampasimanolotra. Grows in moist lowland forest, on gentle to steep slopes, between 400 and 1,100 m.

Description

Majestic solitary palm. TRUNK 20-30 m high, ventricose, about 26 cm in diam., diameter just below crown about 18 cm (with internodes 5 cm, scars 3 cm); bark pale brown, internodes 8-9 cm, scars about 2 cm; wood white, soft, with thin outer layer of hard wood with black fibres. LEAVES 14-26 in the crown, porrect, held on edge distally, with absent, main veins 3-5. STAMINATE INFLORESCENCE solitary (deduced from dead material), at least 130 cm, branched to 2 orders; peduncle > 35 cm, distally 2.2 x 1.5 cm; loose peduncular bract at least 120 cm; rachis > 55 cm; rachillae 13-27 cm, 1 mm across. PISTILLATE INFLORESCENCE solitary, pendulous in fruit, about 150 x 85 cm, branched to 1 order; peduncle 64-77 cm, orange-green, glabrous, proximally about 5 x 3 cm, distally 2.6 x 1.8 cm; prophyll 13-17 x 10-22 cm and thin, fibrous, white, disintegrating; peduncular bracts 20-33 x 6-8 cm (inserted at 7-13 cm from the base of the peduncle), 47-53 x 8 cm (inserted at about 15 cm), 87-98 cm (inserted at 15-26 cm), 89-104 x 4.5 cm (inserted at 43-44 cm); rachis 43-52 cm, pale green, floccose-tomentose to glabrescent, pale green; rachillae 45-50 in number, 18-45 cm, 4 mm across but the bulbous base 15 mm across, pale green, slightly reflexed to spreading, zigzag; pedicel 2-3 mm; (the following measurements from bud material) calyx connate for 1.4 (2 in fruit) mm, 2.3 mm across, free lobes 1.1 x 1.2 mm; petals 2.8-3.3 x 1.7 mm; staminodes 10, about 1.4 mm high; ovary 2.3 mm, 1.5 mm across. FRUIT orange, subglobose, 27-30 x 25-28 mm, one-seeded, with the stigmatic remains subapical, calyx in fruit increasing to a sub-woody cup-like structure 4.5-6 mm across and 2-3 mm high, with faint indications of the calyx lobes, and occasionally with a remnant of a petal. SEED dark brown, 18-20 x 16-21 mm, with large hilar spot (?). EOPHYLL pinnate. (J. Dransfield and H. Beentje. 1995)/Palmweb. Editing by edric.

The ten staminodes in the pistillate flower are unique within the genus. In November 1994 we saw a population of a very large Ravenea species on Vatovavy, south of Mananjary. These spectacular palms appeared to have large fruits, much larger than in R. robustior, but we could not obtain any. It is possible that this is a second colony of R. krociana, although the wood seemed fairly hard. (J. Dransfield and H. Beentje. 1995)/Palmweb.

Culture

"Ravenea krociana and robustior are very very similar and sometimes wrongly tagged in Botanic gardens etc, the stand out difference is that Robustiors leaflets are "thinner" and having grown/growing both Krokiana is a faster grower than Robustior." (Pete) Cold Hardiness Zone: 10a

Comments and Curiosities

This is a dioecious genus.

This has very much the appearance of R. robustior but lacks the hard outer wood of that species; it has a very restricted distribution. The species is named for Ray Kroc, the founder of McDonald"s; this organization funded a 4-year Madagascar Palm Project at Kew, during which period HB discovered R. krociana. (Rakotoarinivo, M. & Dransfield, J. 2012)/Palmweb.

Conservation: Known from five widely separated sites in the southeast, in each site individuals are quite numerous and the whole population is estimated to number about 700 mature trees. The extent of occurrence is 10, 241 km² within the Vulnerable threshold, but the area of occupancy is 450 km² which meets the threshold for Endangered. Although almost all of the sites are inside protected areas there is continuing decline in the extant and quality of the habitat outside of the protected areas and even with some of the protected areas. Hence this species is listed as Endangered. The main threat to this species is habitat loss through clearance for shifting agriculture and logging. Almost all of the known sites are in protected areas: Mangerivola, Midongy Atsimo and Andohahela. (Rakotoarinivo, M. & Dransfield, J. 2012)/Palmweb.

This very tall and stately tree palm is similar to R. robustior and grows only in a small area in the very south of Madagascar. It should be an easily cultivated palm for the tropics and subtropics. (RPS.com)

This is a tillering palm, it exhibits saxophone style root growth (it has a heel), keep top third of heel above soil elevation!


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).

Dransfield, J. & Beentje, H. 1995. The Palms of Madagascar. Royal Botanic Gardens, Kew and The International Palm Society.


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

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