| Pritchardia (pritch-AHR-dee-ah) |
3. Pritchardia mitiaroana: group of palms in makatea scrtb. (Photographs by Yves Ehrhart.)
Habitat and DistributionMoist forest on rough karst limestone, Mitiaro Island of the Cook Islands, and
Pritchardia mitiaroana is a solitary, rather robust, stocky, fan palm. It is bisexual and flowers for a number of years (pleonanthic) instead of flowering once and dying. Trunk: 4-6(-10) m tall, slightly ventricose, widening to 30-35 cm diam. at 1.5 m above the ground, tappering above, grey brown, obscurely ringed with leaf scars, smooth or with irregular shallow vertical fissures and emitting a hollow, resonating, drum-like sound when sharply struck. Crown: Comprising 16-23 expanded leaves in terminal cluster, the leaves held stiffly. Leaves: Petiole 80-90 cm long clasping the stem, the margins smooth, the surfaces somewhat waxy, glabrous; leaf base fibrous. Lamina bright green, briefly costapalmate, slightly undulate, 100-110 cm long with 60-66 folds in leaves of mature palms, the blade split to ca. 30 cm deep into stiff or slightly drooping segment, the segments ca. 5.5 cm wide. Upper surface glabrous, underneath covered surface abundantly but incompletely covered with in a thin layer of white wax and punctiform dark brown scales. Inflorescences (Panicles): Infrafoliar, somewhat lax, shorter than or about equaling petioles in flower and fruit, branching to 3-4 orders. 10-12 inflorescences and infructescences present at the same time (appearing one after the other during several months, with apparently no flow-ering during the cool season). Peduncle ca. 60 cm long white tomentose. Rachis somewhat zig-zag. Rachillae scarcely crowded, pale yellowish-green, up to 10 cm long, about 2 mm in diam, glabrous, bearing solitary flowers about 4 mm apart. Fruit: Globose, smooth, glabrous, green becoming brownish-black to 7 mm across, borne on the persistent calyx. Style and carpel remains apical. Seed: 5.5 mm across, brown. (llifle.com) Editing by edric.Solitary, rather robust, stocky, pleonanthic hermaphroditic fan palm. Stem at maturity 4-6 m tall, slightly ventricose, widening to 30-35 cm in diam. at 1.5 m above the ground, then tapering slightly to about 25 cm in diam. at 2.5 m height, diameter then constant to the base of the crown, the stem surface grey brown, obscurely ringed with leaf scars, smooth or with irregular shallow vertical fissures in young palms or near the stem apex. Crown comprising 16-23 expanded leaves, one leaf three-quarters expanded, a sword leaf and two or more dying or dead leaves, juvenile palms (up to 3.5 m tall) with about 16 leaves, adult palms (up to 5 m tall) with 23 leaves, the leaves held stifly; petiole 80-90 cm long, about 20 cm wide at the base, the base clasping the stem, tapering to 6 x 1.2 cm at about 50 cm above the base, tapering gradually to 3 x 1 cm at the insertion of the blade, the margins smooth, the surfaces somewhat waxy, glabrous; leaf base fibrous, terminating in a triangular ligule about 50 cm above the base, the fibres soft, pale grey brown; adaxial hastula bluntly triangular,4 x 3 cm, + symmetrical, abaxial hastula absent; leaf-blade bright green, briefly costapalmate, 100-110 cm long at the mid-point, held + flat or folded into a shallow "m",
|52-56 folds in leaves of juvenile palms, 60-
66 folds in leaves of mature palms, the blade split to about 30 cm deep into stiff induplicate segments, the segments about 5.5 cm wide at the base of the splits, inter-segment fibers present in newly expanded leaves; adaxial surface ofblade glabrous, abaxial surface covered in a thin layer of white wax and bearing abundant evenly distributed punctiform dark brown scales. Inflorescences solitary in each leaf axil, shorter than and hence obscured by the leaves, branching to 3-4 orders, the inflorescence somewhat lax, not congested, 10- 12 inflorescences and infructescences present at the same time (appearing one after the other during several months, with apparently no flowering during the cool season); peduncle about 60 cm Iong, flattened at the base where about 3 x 1.5 cm, distally elliptic in cross section, about 2.0 x 1.3 cm; prophyll about 22 x 5.5 cm, tubular, 2-keeled, tattering apically, densely white tomentose; peduncular bracts 5-6, up to about 40 x 4 cm, tattering as the prophyll and bearing white tomentum; inflorescence rachis somewhat zig - zag; rachillae numerous but scarcely crowded, pale yellowish-green, straight or somewhat curved, up to 10 cm long, about 2 mm in diam., glabrous, bearing solitary flowers ca. 4 mm apart,.each subtended by a fragile brown ligulate acuminate membranous rachilla bract, about I.7 x 0.1 mm; flower scar ca. 0.7 mm in diam. Flower bud 6.5 x 2.8 mm; calyx with a basal tube, 3.5 mm long, with three short triangular lobes to 0.5 mm long, glabrous, faintly striate; corolla tubular below, circumscissile just below the mouth of the calyx tube, the lobes accrescent, about 4 x 2 mm, striate, glabrous, the inner surface marked with anther impressions; stamens 6, filaments united in an epipetalous ring about 1.6 mm high, with free filaments to 1.5 mm; anthers medifixed, versatileo -F oblong, 2.5 x 1 mm introrse; gynoecium with 3 carpels free in the wedge-shaped ovarian portion Io 2 x 1 mm, api cally connate in a style to 2 x 0.8 mm. Fruit rounded, to 7 mm in diam., borne on the persistent calyx, the calyx lobes and androecial ring explanate; style and carpel remains excentrically apical; epicarp smooth, glabrous, green becoming brown; mesocarp ca. 0.6 mm thick; endocarp crustaceous, about 0.1 mm thick. Seed basally attached, about 5.5 mm in diam., testa very thin, brown; endosperm homogeneous, embryo subbasa. (Dr. John Dransfield and Dr. Yevs Ehrart)
Pritchardia mitiaroana occurs in several small groups and isolated trees scattered on the western and southwestern side of the island, in the inner maka.tea(maltateais the Polynesian name for the soils and geographic areas located on raised coral limestone reefs). No single plant species predominates in any area. The vegetation is low scrub, about 3 m tall. The soils (Wilde l98I) have formed from the nl,alratea limestone rock in situ and from rock fragments. There is little sand, and very little organic matter accumulates between the rock fragments. It is very sharply drained. According to USDA Soil Taxonomy, it is a sandy-skeletal carbonatic isohyperthermic lithic Rendoll. Climatic data are scarce but data from the neighboring island suggest that the mean annual rainfall is about 2,000 mm distributed throughout the year, the driest months being June to August and the wettest December to February. Temperatures range from 21.5" C to 26.9" C with the coldest months being the driest. Mean relative humidity is about 85%. (Dr. John Dransfield and Dr. Yevs Ehrart)
To 10 m tall; proximal margins of petiole, moderately and coarsely fibrous; stem smooth, moderately to dark gray, slightly ventricose, emitting a hollow, resonating, drum-like sound when sharply struck with the knuckles of the closed fist; leaf blade slightly undulate, divided 1/4-1/3, abaxial surface white-waxy, abundantly but incompletely covered with lepidia, segment tips stiff or slightly drooping; inflorescences composed of 1 panicle, shorter than or about equaling petioles in flower and fruit, panicles branched to (3 or) 4 orders, rachillae glabrous; fruits 5-7 mm in diam., globose. (Hodel, D. 2007)/Palmweb.
The smooth, gray, slightly ventricose trunk, which emits a hollow sound when struck, is by itself sufficient to distinguish Pritchardia mitiaroana in life. The highly ramified, large panicles typically branched to four orders and very small fruits are also distinctive. Wilder (1934) erroneously referred to and illustrated this species as P. vuylstekeana. It is difficult to traverse the thick, scrubby vegetation (frequently with numerous Pandanus with their exceedingly prickly leaf margins) and rocky, sharp, uneven terrain where Pritchardia mitiaroana occurs on Mitiara and Makatea Islands. On Makatea it is especially difficult and even dangerous because the terrain is rather densely punctuated and pockmarked with precipitous depressions, many of them up to five meters deep or more unwary explorer. Although some of these holes are natural, many are the result of extensive phosphate mining that once occurred on Makatea. The mining and accompanying destruction of vegetation probably also devastated the populations of P. mitiaroana on the islandi relatively few individuals exist there today. Fortunately, the species is more common on Mitiara, and jean-Yves Mayer reported (pers. comm.) that on Niau, not too far from Makatea, it is especially abundant, with about 1000 reproductive individuals and numerous juvenile plants. (Hodel, D. 2007)/Palmweb.
Pritchardia mitiaroana is an easy to grow palm but not often available for the landscape. Pritchardia mitiaroana vary in shape. Specimens raised in dry and/or infertile soils tend to be smaller in stature with smaller leaves. Light also affects the plant's form while those grown in full sun are more compact. This palm prefers a sunny, well drained, and moist location. Growth rate: It is a slow growing, short stocky palm. Soil: It likes organic soil, but is adaptable to clay and loam bolth slightly alkaline and acidic. Good drainage is also important. Fertilization: Need a perfect fertilizer diet including all micro nutrients and trace elements or slow release fertilizer. Micronutrient deficiencies are occasional problems. If it doesn't get enough Mn and Fe, the leaves take on a rather unhealthy yellow colour. Micronutrient deficiencies only show up on soil with a high pH. Fertilize often for faster growth. Water Requirements: Needs regular water, do not let dry out between waterings. however it does not want to sit in continually wet, mucky soil. The roots and lower trunk can rot if soil is kept too moist. Light: Prefers full sun but will tolerate half day sun. Hardiness: It is adapted to tropical and subtropical climates, young plants are more cold sensitive. Maintenance: Remove dead fronds and spent fruiting stalks for a clean landscape appearance. Fronds can be left on the palm to form a skirt for natural settings. Palms recycle nutrients from dead or dying fronds and use them for healthier fronds. Palms only have a set number of new leaves that can sprout and grow per year and removing fronds will not increase that number. If you cut off more than what will grow annually, you could be left with a pretty bare and bald palm. Pest & Disease: Mealybugs and whiteflies underneath the leaves can present problems at times if not kept in check. A generous spray of water can wash them off. Ornamental: It is cultivated as an ornamental tree, and planted in gardens and parks in tropical and sub-tropical climates either as a single specimen or in groups. Culture in containers is possible although growth rates are slower. A bright patio will provide an excellent environment for young specimens which can eventually be planted in a sunny location. (llifle.com)
"Apply a complete palm fertilizer with minor elements as directed on label. Be certain that sufficient magnesium and potassium is present in the fertilizer component. This is especially critical for loulus in pots. Magnesium and potassium deficiencies are two of the most serious nutritional disorders in palms. The deficiencies are characterized by bright yellowing (chlorotic) on leaf edges or streaking or the entire fronds yellowing. This can be difficult to reverse. Applications of Epsom salt, or magnesium sulfate (MgSO4), is good but does not last and is usually washed out of the soil in rainy periods. There are some very good slow release fertilizer spikes made for especially for palms on the market which contain a good balance of minor elements with magnesium and potassium. Potted or younger loulu planted in the ground appreciate a foliar feeding of kelp or fish emulsion and Epsom salt monthly or bi-monthly. [David Eickhoff, Native Plants Hawaiʻi." (Encyclopedia of Life curator Dr. David Eickhoff)
Loulu are prone to leaf rollers, red spider mites and sugar cane borers. Rats will eat its fruit. (Encyclopedia of Life curator Dr. David Eickhoff)
Comments and Curiosities
Etymology: Pritchardia name is dedicated to William Thomas Pritchard (1829-1907), British official stationed in Fiji in the 19th Century, British counsul in Fiji, adventurer, and author of Polynesian Reminiscences in 1866.
Conservation: Globally endangered (seriously). Comment: Known from about 500 plants in a very restricted area in the southwest makatea scrubland of Miti‘āro. (cookislands.bishopmuseum.org)
KEY FEATURES: Solitary palm. STEM smooth without scars, to 6 m, 35 cm. LEAVES 25 in terminal cluster; stalk 90 cm, smooth margin, tapering; BLADE bright green, 110 cm long, 65 folds, split inward 30 cm. INFLOR: to 1 m, branching. FLOWERS bisexual, small, 3 mm. FRUITS round, to 7 mm, brownish-black. SEED 5 mm, brown. (cookislands.bishopmuseum.org)
- Glossary of Palm Terms
- MODERN BOTANICAL LATIN
- "Just To Be Clear"
- A New Species Of Palm From Mitiaro Island
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).
Dr. John Dransfield and Dr. Yevs Ehrart
Hodel, D. 2007.
Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.