Socotra Dragon's Blood Tree (Dracaena cinnabari): Vulnerability of Intricately Branched Giving Tree

The three common names Dragon Blood Tree, Dragon's Blood Tree and Socotra Dragon Tree all designate one tree:  Dracaena cinnabari.

The tree is in the family Asparagaceae, whose asparagus and asparagus-like plants flower from one embryonic leaf. It is in the subfamily Nolinoideae, most of whose members have lily-like tepals, comprising petals (Latin: petalum, “petal”), which are the colorful modified leaves that protect the floral reproductive parts, and sepals (Latin: separatus, “separate” and petalum, “petal”), which are the oftentimes green parts that protect the petals. It is in the genus Dracaena (Greek: δράκαινα, drakaina, "female dragon"), whose members mostly are succulent shrubs but also include six stout trees. It is in the species cinnabari (Greek: κιννάβαρι, kinnabari), whose hallmark characteristic is the vermilion color of the plant’s resin.

As of July 2008, the entire archipelago is a United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Site. The designation honors the unique animal and plant life of the four islands (Socotra, Samhah, Darsa, Abd al Kuri) and two rocky islets (Ka’l Fir’awn and Sābūnīyah) which make up the archipelago. It reflects UNESCO’s concern over the survival of the archipelago’s 825 biologically diverse species, of which 307 are found nowhere else on earth and of which one is the Dragon’s Blood Tree.

Indeed, survival is a major concern in terms of the Dragon’s Blood Tree. The tree’s status is considered vulnerable by the International Union of the Conservation of Nature and Natural Resources (IUCN). Vulnerability acknowledges the danger of  extinction from threats to the tree’s survival and reproduction. Threats include the following:

1. Drop in moisture levels from decreased incidences of monsoon drizzle, morning dew and mountain mists;

2. Drought;

3. Grazing by the island’s 30,000+ goats;

4. Harvesting by islanders;

5. Lack of regeneration due to reduced flowering, fruiting and seeding as well as high seed mortality;

6. Population pressure;

7. Road construction.

Lieutenant James Raymond Wellsted, FRS (1805-October 25, 1842) is the first known European discoverer of the tree. He arrived in 1835 by way of the East India Company’s survey ship Palinurus, under Captain Stafford Bettesworth Haines (1802-1860). He spent two months on the isolated Indian Ocean island, about which he wrote Memoir on the island of Socotra. His mission was a survey of the island for the Indian Government. The map which was produced, with the coastal waters charted by S.B. Haines and the interior surveyed by J.R. Wellsted, is the basis for the large scale Admiralty Chart which is still used by the Royal Navy today. During the course of the survey, the Dragon’s Blood Tree was described and named Pterocarpus draco (Greek: πτερον, pteron, “wing” + Latin” carpus from Greek: καρπός, karpos, “fruit”; Latin: dracō from Greek: δράκων, drakōn, “dragon”).

But the name did not last even half a century. In 1880, Scottish botanist Sir Isaac Bayley Balfour, FRS FRSE (March 31, 1853-November 30, 1922) examined the plant and wrote a formal description of the species. He renamed the tree Dracaena cinnabari.

The tree has an unusual look which is compared to that of a giant mushroom or a gigantic upside-down umbrella.

Bark, branches and trunk:

The Dragon’s Blood Tree grows slowly, at a yearly rate of about 4 inches (10.16 centimeters). It matures to a height of 10 to 20 feet (3.048 to 6.096 meters) and a diameter of 12 to 18 inches (30.48 to 45.72 centimeters).

The tree's stout, straight trunk has a fissured bark which becomes more fissured with resin harvesting. The trunk grows until its first flowering. After that, growth switches to the formation of branches which grow out of the trunk in a fashion which is called dichotomous (Greek: διχότομος, dikohotomos, "cut [in two from] one part") branching. Consequently, each branch which grows out of the trunk grows two sections, each of which grows two sections, etc. Scientists Radim Adolt and Jindrich Pavlis esimate that a tree will grow a total of 1,056 branches. Each branch will be made up of a series of sausage-shaped sections, to a total of 17 and at an estimated age of 13 to 29 years per section.

A large, dense crown thereby forms to minimize evaporation. The canopy gives shade and channels humidity from dew, mist and rainfall down the branches and trunk and into the ground for dissolved nutrient uptake by tree roots. The shade and the anti-evaporation measures help both the tree and the tree’s seedlings which often grow beneath their parent.

The crown also helps estimate tree age. Scientists Radim Adolt and Jindrich Pavlis indicate that years are counted, not by the equivalent of yearly growth rings, but by adding the age of the tree's crown to the time of the tree's first flowering. They thereby obtain an age range between 200 and 300 years for their sample of 50 trees. They suggest that within 3 to 7 decades both the oldest trees, which may be around 350 years old, and newer generations will be reduced in number to isolated rarities headed towards extinction on Socotra.

Leaves:

The Dragon’s Blood Tree is known as a rosette tree, because its evergreen leaves grow only at the ends of the youngest branches. The process of dropping old leaves and bringing forth new leaves occurs seamlessly every 3 to 4 years.

The shape of the stiff, upright, waxy leaves is reminiscent of a sword. The broadest width occurs at the leaf's base, which attaches directly, without peduncle (Latin: pedunculus, "footstalk," diminutive of pes, "foot") or stalk, to a branch. Each leaf measures 11 to 23 inches (30 to 60 centimeters) long and about 1 inch (2.5 centimeters) wide.

In his description, Lieutenant Wellsted noted the effect of leaves, which "resemble the leaves of the pine-apple" and which extend "in an indefinite number" to ". . . assume a fan-like shape; . . . and their variety in shape and distribution gives rise to most fantastic appearances." (J.R. Wellsted, p. 198)

Flowers:

The fragrant flowers appear at the ends of branches in February and bloom in June. Their colors range from cream to light green, tan or white. They cluster in groups of 2 to 3 on stalks 1/5 inch (5.08 millimeters) long. The flowers of a Dragon’s Blood Tree are complete. They are self-fertilizing because they have all the parts which are needed for floral reproduction to take place.

Fruit:

Over the course of five months, the tree's small, fleshy, spherical berries change in color from an initial green, to black and then orange red. They grow on the floral clusters and may number over 500 per panicle (Latin: pānicula, "tuft" diminutive of pannus, "thread" from Greek penos, "web"). They will drop to the ground if they are not consumed within one year.

Seeds:

Each berry contains 1 to 3 seeds. Each seed measures about 1/5 inch (5.08 millimeters) in diameter and weighs about 0.15 pounds (68 grams). Scientists Radim Adolt and Jindrich Pavlis estimate that over 600,000 seeds may be produced during a tree's life span.

The Dragon's Blood Tree grows in evergreen and semi-deciduous woodlands. In central and western Socotra, these woodlands form on the granite rocks of the Haggeher Mountains as well as on the limestone plateaus near Diksam, Firmihin, Rewgid and Reyged. The trees also may be found scattered around Hamaderoh, Homhil and Igliso in the east. Their locations overlap with the places which receive the greatest drizzle from the island’s northeastern and southwestern monsoons.

1. Average yearly temperature between 62.2 °F (16.7 °C) and 93.6 °F (34.2°C):  Temperatures fall between 60 and 69 °F (15.5 and 20.5 °C) from October to March. The coldest months are December through February. In contrast, temperatures rise above 90 °F (32.2 °C) between April and June and then in August and September. The hottest month is May.

2. Average yearly rainfall of 10 inches (254 millimeters):  Rain falls in excess of 1 inch (25.4 millimeters) only in the months of May, September and October. The rainiest month is May, with an average rainfall of almost 1-1/2 inches (38.1 millimeters). But June through August are rainiest, in terms of number of rain days. Specifically, the three summer months have 6 to 9 rainy days, as opposed to a general trend of 2 each in January through March; 3 each in April and October through December; and 4 each in May and September.

3. Average yearly humidity around 20%:  Fierce winds, high heat and intense light are responsible for low atmospheric and terrestrial moisture contents. The least humid months are June through August, November to December, and February to March, when humidity remains below 20% In contrast, levels climb to over 35% in May and October.

4. Alkaline, calcareous soils:  The Dragon’s Blood Tree grows in calcareous soils at altitudes of 1,640 to 4,921 feet (500 to 1,500 meters) above sea level. Such soils may exhibit alkaline pH levels well above the generally neutral 6.5 to 7.0 range within which many houseplants and ornamentals flourish. The reason lies in the weak carbolic acid presence in soils which are strong on calcium and magnesium nutrient content and which are affected by the island’s basic geography as a limestone plateau that transitions to granite slopes on the one hand and to coastal plains on the other.

5. Drainage that holds onto nutrients but does not pool:  Cracking may be evidenced in the ground out of which the Dragon's Blood Tree grows. The cracking allows moisture to percolate in controlled fashion down to the tree's roots.

6. Nutrients from air, ground and water:  Trees need 17 nutrients for life promoting and sustaining activities: carbon, hydrogen and oxygen from the air and water as well as boron, calcium, chlorine, cobalt, copper, iron, magnesium, manganese, molybdenum, nitrogen, phosphorus, potassium, sulphur and zinc from the ground. Plant growth is affected by the absence, overabundance or scarcity of any one of these nutrients. A soil pH level that is low (acidic) or high (alkaline) can make unavailable nutrients which actually are present. For example, alkaline pH levels are linked with deficient or unavailable amounts of calcium, iron, magnesium, manganese, phosphorus and sulfur.

7. Propagation by seeds:  Seedage is the only means of propagation. In the wild, seedlings either grow around the parent tree or elsewhere on the western mountains and plateaus through seed dispersion by birds, livestock and winds. In cultivation, the seed must be planted about 2 inches (5.08 centimeters) down in a starter pot of a gritty, pumice mix. There must be good drainage, whereby the pot never becomes waterlogged even though the seed always is in the midst of slight moisture. The seed needs at least 7 hours of indirect light. Germination may take 2 to 3 months. Watering can be done every 7 to 10 days, with adjustments if roots become waterlogged or dry out.

It is suggested that the Dragon’s Blood Tree is hardy to 30 to 40 (°F (-1.11 to 4.44°Celsius). But in fact it is best to avoid frozen soils and temperatures below 50 degrees F (10 °Celsius).

Every part of the Socotra Dragon’s Blood Tree has a use.

The trunk:  Traditionally, the trunk is the source of wood for crafts, fixtures and structures. In modern times, it serves as wood for beehives, which are made for export to the mainland.

The resin:  According to Greek mythology, the 100-headed dragon Ladon guarded the Garden of the Hesperides, who were the three nymph daughters of Atlas, the Titan who supported earth and heaven. As part of quest fulfillment, the hero Hercules managed to take three of the garden’s forbidden golden apples. Depending upon the version of the myth, Ladon was killed either by a quest-focused Hercules or an enraged Atlas. Either way, from Ladon’s spilled blood sprang forth the world’s Dragon Trees.

According to the historical record, the phrase dragon’s blood dates back to the first century A.D. In fact, the phrase is used in terms of its source on Dioskouridou (“Of Dioscorides”), according to the Περίπλους τὴς Ἐρυθράς Θαλάσσης (“Periplus of the Erythraean Sea”). The name Dioskouridou is a Greek name for Socotra and derives from the Greek herbalist Pedanius Dioscorides (c. A.D. 40 - 90) who included Socotra dragon's blood in his Περὶ ὕλης ἰατρικῆς ("Concerning Medical Materials"). The word περίπλους (periplous) literally translates as “a sailing around.” The words Ἐρυθράς Θαλάσσης literally refer to the Red Sea but include the Persian Gulf and Red Sea as well.

Dragon’s blood was and is highly prized throughout the world as effective in meeting a host of human needs. For example, traditionally it includes among its uses the following:

1. Alchemy and ritual magic;

2. Breath freshener;

3. Color of blood in paintings;

4. Decoration for houses and pottery;

5. Dye for wool;

6. Lacquer for furniture and varnish for violins;

7. Lipstick;

8. Medicine in the treatment of diarrhea, dysentery, fevers, tumors, ulcers and upset stomachs as well as in the promotion of blood coagulation and wound healing.

Research conducted by scientists Deepika Gupta, Bruce Bleakley and Rajinder K. Gupta in fact shows that the dragon blood red resin of the Socotra Dragon’s Blood Tree has the necessary compounds for analgesic, antimicrobial, antioxidative, antithrombotic, antitumor, antiviral, cytotoxic and hemostatic activities.

The leaves:

Traditionally, the leaves are sources of food, medicine and tools. Cattle and goats may be fed the leaves during the summer and times of drought. But they only can handle about 5 to 8 at a time, because of the medicinal properties of the leaves. In fact, the leaves treat for gas in the gastrointestinal tract. They also have practical use in the making of traditional rope.

The fruit:

Food is the traditional use of the berries. Socotra starlings (Onychognathus frater) perch on top of the trees and peck at the ripening berries. Additionally, islanders feed the berries to cattle and goats during the summer and times of drought. The berries may have an unsettling effect on the digestive systems of livestock. Islanders therefore try to limit consumption to 5 to 8 berries per feeding time.

The roots:

Gum resin is obtained from the roots for the following uses:

1. Astringent agent;

2. Component in gargle water and toothpaste;

3. Treatment for rheumatism.

The Socotra Dragon's Blood Tree has yet another critically important use, which is scientific. Weighty responsibilities indeed rest upon all of the tree's constituent parts. Specifically, the tree is considered one of the most distinctive, iconic and necessary plants on the island of Socotra. In fact, conservationists and scientists unite to place the tree into three important categories:

1. Flagship species, as the rallying point for conservation awareness;

2. Indicator species, as the key measure of critical changes in the environment and the main sign of ecological catastrophe if it goes extinct;

3. Umbrella species, as the one species upon which the survival of other threatened species depends.

Socotra Dragon's Blood Trees are living fossils whose arboreal and botanical lineage tracks backwards to times far beyond the outer limits of human memory. Indeed, they are the descendants and relatives of trees which survived the breakup of the supercontinent Laurasia into North America and Eurasia about 200 million years ago. They thrived in closed forests as well as on cliffs, escarpments and rocky slopes until desertification, population pressure and predation left them habitat-less other than on Socotra. But even there, they now occupy just 5% of their original range.

In their vulnerability, Socotra Dragon's Blood Trees typify the struggle of many prehistoric plant and animal species which are found only in a specific geographical location. Change, which has characterized their extensive existence, has always been surmounted. Nevertheless, the cumulative weight of time and change in combination with their specific sense of geographic place appear to be conspiring against these giving trees, which provide more than "most fantastic appearances".

This hub is dedicated to the memory of James Raymond Wellsted, who passed away on October 25, 1842, at the young age of 37.

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Socotra Dragon Blood Tree: Boris Khvostichenko (Boriskhv), CC BY SA 3.0, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Socotra_dragon_tree.JPG

Dragon Blood Trees at Yehazahaz, Mt Haghier's southern slopes: Theodore Bent-Southern Arabia (1900), opp p. 387, Public Domain, via Project Gutenberg @ https://www.gutenberg.org/files/21569/21569-h/21569-h.htm

Socotra in the Indian Ocean: Central Intelligence Agency, Public Domain, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Somali_map.jpg

Socotra Dragon's Blood Tree: a vulnerable, endemic tree with a view: HopeHill, CC BY 2.0, via Flickr @ https://www.flickr.com/photos/45340412@N06/4552875452/

Socotra Dragon Blood Trees in a Socotran's back yard on Diksam Plateau: Gerry and Bonni, CC BY 2.0, via Flickr @ https://www.flickr.com/photos/gerr-bon/6408238083/

August 1, 1835, nautical chart of Socotra compiled by James Wellsted and S.B. Haynes from Bombay Marine officer surveys 1820-1829: Public Domain, via Qatar Digital Library @ https://www.qdl.qa/en/archive/81055/vdc_100023868004.0x000010

closeup of intricate branching of Socotra Dragon's Blood Tree: HopeHill, CC BY 2.0, via Flickr @ https://www.flickr.com/photos/45340412@N06/4438832647/

drawing by Lieut. C.J. Cockburn, lithograph by John Nugent Fitch (1843-1927): Isaac Bayley Balfour-Botany (1888), Table XCVI, Public Domain, via Internet Archive @ https://archive.org/details/transactionsofro311888roy/page/n914/mode/1up?view=theater

lithograph of Dracaena cinnabari by John Nugent Fitch: Figs. 1,2,3,4,9 natural size; rest magnified: Isaac Bayley Balfour-Botany (1888), Tab. XCVII, Public Domain, via Internet Archive @ https://archive.org/details/transactionsofro311888roy/page/n918/mode/1up?view=theater

illustration by botanist Georg Schweinfurth (1836-1925): G Schweinfurth-The Heart of Africa (1874), Vol I, p21, Public Domain, via Internet Archive @ https://archive.org/details/heartofafricathr01schw/page/n48/mode/1up?view=theater

Dragon's Blood Trees and Socotra's rugged landscape seem a perfect match, made for each other: HopeHill, CC BY 2.0, via Flickr @ https://www.flickr.com/photos/45340412@N06/4439493066/

lunch and pleasing vista under Socotra Dragon Blood Tree: Gerry and Bonni, CC BY 2.0, via Flickr @ https://www.flickr.com/photos/gerr-bon/6408236747/

Socora pottery with pigment from dragon's blood tree resin ~ Liverpool Museum: H.O. Forbes-The Natural History of Sokotra (1903), frontispiece, Public Domain, via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/24884212

Young Socotra Dragon's Blood Trees: flourishingly cultivated in Koko Crater Botanical Garden, Honolulu: Daderot, Public Domain, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Dracaena_cinnabari_-_Koko_Crater_Botanical_Garden_-_IMG_2295.JPG

1898-1899 photograph by Henry Ogg Forbes (1852-1932): The Natural History of Sokotra, p. xl, Public Domain, via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/24884196

Socotra Dragon Blood Tree: oil on gallery canvas by Chris-Cloud: Chris-Cloud, CC BY-SA 3.0, via deviantART @ https://www.deviantart.com/chris-cloud/art/Dragonblood-Tree-186422364

Socotra golden-winged Grosbeak: lithograph by Dutch zoological illustrator Joseph Smit (July 18, 1836–Nov 4, 1929): P.L. Sclater-On the Birds Collected in Socotra (1881), Plate XVII, opp p170, Public Domain, via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/30759298

Charaxes balfouri: lithograph by Maud Horman-Fisher: HO Forbes-Natural History (1903), Plate XIX (p. 319), Public Domain, via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/24884570

Adolt, Radim; Pavlis, Jindrich. (2004). “Age structure and growth of Dracaena cinnabari populations on Socotra”. Trees – Structure and Function, 18 (2004): 43-53.

Balfour, Isaac Bayley. “Botany of Socotra.” Transactions of the Royal Society of Edinburgh: Earth Sciences. Volume XXXI (31). Edinburgh: Robert Grant & Son; London: Williams & Norgate, MDCCCLXXXVIII (1888).

• Available at Google Books at:  http://books.google.com/books/about/Transactions_of_the_Royal_Society_of_Edi.htmlid=dB5XAAAAYAAJ

Balfour, Isaac Bayley. Botany of Socotra. Forming Vol. XXXI of The Transactions of the Royal Society of Edinburgh. Edinburgh: Robert Grant & Son; London: Williams & Norgate, MDCCCLXXXVIII (1888).

• Available at Biodiversity Heritage Library at:  http://www.biodiversitylibrary.org/item/42457
• Available at Internet Archive at:  http://archive.org/details/botanyofsocotra00balf

Bent, Theodore, and Mrs. Theodore Bent. Southern Arabia Soudan and Socotra. With a Portrait, Maps, and Illustrations. London: Smith Elder & Co., 1900.

• Available via Google Books at:  http://books.google.com/books/about/Southern_Arabia.htmlid=jNoTAAAAIAAJ.
• Available via Project Gutenberg at: www.gutenberg.org/files/21569/21569-h/21569-h.htm

Botting, Douglas. Island of the Dragon's Blood. London: Hodder and Stoughton, 1958.

Boxhall, P.G. "Socotra: 'Island of Bliss.'" The Geographical Journal, Volume 132, Number 2 (June, 1966): 213-222.

Baumer, Ursula, and Patrick Dietemann. (2010). "Identification and differentiation of dragon's blood in works of art using gas chromatography/mass spectrometry." Analytical and Bioanalytical Chemistry, 397 (2010):1363-1376.

Cheung, Catherine, and Lyndon DeVantier. Socotra: A Natural History of the Islands and their People. Hong Kong: Odyssey Books & Guides, 2006.

“Decisions Adopted at the 32nd Session of the World Heritage Committee (Quebec City, 2008)." United Nations Educational, Scientific and Cultural Organization Convention Concerning the Protection of the World Cultural and Natural Heritage World Heritage Committee Thirty-second session Quebec City, Canada 2-10 July 2008. World Heritage 32 COM. WHC-08/32.COM/24 Rev 31 March 2009. Paris, France: UNESCO World Heritage Centre, May 2009.

• Available at:  http://whc.unesco.org/archive/2008/whc08-32com-24reve.pdf

“Dragon’s blood tree (Dracaena cinnabari)". ARKive Images of Life on Earth: Plants and algae. 2003-2011.

• Available at:  http://www.arkive.org/dragons-blood-tree/dracaenacinnabari/image-G70994.html

Forbes, Henry O., ed. The Natural History of Sokotra and Abd-el-Kuri: Being the Report upon the Results of the Conjoint Expedition to these Islands in 1898-9, by Mr. W.R. Ogilvie-Grant, of the British Museum, and Dr. H.O. Forbes, of the Liverpool Museums, together with information from other available sources Forming A Monograph of the Islands. Liverpool-London: The Free Public Museums, 1903.

• Available via Biodiversity Heritage Library at:  http://www.biodiversitylibrary.org/item/80063
• Available via Internet Archive at:  http://archive.org/details/naturalhistoryof00forb

Gupta, Deepika; Bleakley, Bruce; Gupta, Rajinder K. “Dragon’s blood: botany, chemistry and therapeutic uses.” Journal of Ethnopharmacology, Vol. 115, No. 3 (2008): 361-380.

Miller, Anthony G. (2004). "Dracaena cinnabari". In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.1.

• Available at:  http://www.iucnredlist.org/apps/redlist/details/30428/0

Petroncini, Serena. "Survey and monitoring of Dracaena cinnabari Balf.Fil. in Soqotra Island (Yemen)". In: ETFRN [European Tropical Forest Research Network] News 36: New Instruments for Monitoring and Evaluation: Organisations – Programmes.

• Available at:  http://www.etfrn.org/ETFRN/newsletter/news36/n136_oip7.html

Schweinfurth, Georg. The Heart of Africa. Three Years' Travels and Adventures in the Unexplored Regions of Central Africa from to 1871. Translated by Ellen E. Frewer. With an Introduction by Windwood Reade. In Two Volumes. Vol. I. With Maps and Woodcut Illustrations. London: Sampson Low, Marston, Low, and Searle, 1874.

• Available via Internet Archive at:  http://archive.org/details/heartofafricathr01schw

Sclater, P.L. (Philip Lutley), and Dr. G. Hartlaub. "On the Birds Collected in Socotra by Prof. I.B. Balfour." Proceedings of the Scientific Meetings of the Zoological Society of London for the Year 1881, January 4, 1881: 165-175. London: Messrs. Longmans, Green, Reader and Dyer, 1881.

• Available via Biodiversity Heritage Library at:  http://www.biodiversitylibrary.org/item/96698

Silverstein, Shel. The Giving Tree. New York: Harper & Row, 1964.

Stang, David. (2009). Dracaena cinnabari (Dragon’s Blood Tree). ZipcodeZoo.com, 2004-2011.

• Available at:  http://zipcodezoo.com/Plants/D/Dracaena_cinnabari/

“Socotra Archipelago.” United Nations Educational, Scientific and Cultural Organization World Heritage Convention: The List. UNESCO World Heritage Centre, 1992-2011.

• Available at:  http://whc.unesco.org/en/list/1263

Wellsted, J.R. "Memoir on the Island of Socotra." Journal of the Royal Geographical Society of London, Vol. 5 (1835): 129-229.

• Available via Internet Archive @ https://archive.org/details/s572id13663570/page/129/mode/1up

Wellsted, James Raymond. Travels to the City of the Caliphs along the Shores of the Persian Gulf and the Mediterranean: Including a Voyage to the Coast of Arabia, and a Tour on the Island of Socotra. In Two Volumes. Volume II. London:  Henry Colburn, 1840.

• Available via Google Books at: books.google.com/books?id=S-YDAAAAQAAJ
• Available via HathiTrust at:  http://hdl.handle.net/2027/nnc1.0035548509
• Available via Internet Archive at:  http://archive.org/details/travelstocityca02wellgoog