Part I: From the Botanical Standpoint

TREES AND WOODS OF THE LIGNUM-VITAE FAMILY

The true lignum-vitae belongs to the family Zygophyllaceae. The plants included in this family are mostly herbs, undershrubs, and shrubs; many of them are xerophytic. The only trees of the family belong to three closely related genera, namely Guaiacum, Porlieria, and Bulnesia. These are confined to tropical and sub-tropical regions of the Western Hemisphere.

The genus Balanites is included in the Zygophyllaceae by some botanists, but the structure of the wood has no resemblance to that of the three genera herein described.

Some botanists do not accord generic rank to Porlieria, but include it as a section of the extended genus Guaiacum (see 40, p. 59).

These three genera are composed of mostly evergreen trees and shrubs with opposite, compound, abruptly pinnate leaves, and with showy flowers solitary or in umbel-like clusters. The fruits are 2-5 lobed or parted, and each portion contains usually a single seed.

Guaiacum and Porlieria are alike in having blue or purple flowers, and leathery fruits containing seeds covered with a thin fleshy and often highly colored exocarp. Bulnesia, on the other hand, has yellow flowers, and the fruit, instead of being fleshy, is a 5-parted dry capsule with each part flattened into a conspicuous wing. The seeds are not provided with a fleshy covering.

In Guaiacum the stipules are deciduous, and the stamens are almost invariably without appendages. In the other two genera the stamens have prominent appendages and the stipules of the leaves are persistent, being thorny in Porlieria. The latter genus is further characterized by having small linear leaflets which exhibit nyctitrophic or “sleep” movements, and flowers that are tetramerous instead of pentamerous as they are in the other two.

These trees are found commonly in very dry regions and are accordingly of very slow growth, short-boled and bushy. The trunks, however, are often very stout with little taper. Some of the species of each genus are typically shrubs and others tend to become so in the most unfavorable sites. In the better situations, however, the trees grow more rapidly and are taller, straighter, and smoother, though such timber is not necessarily better and may, indeed, be of poorer quality on that account.

The woods of Guaiacum, Porlieria, and Bulnesia have many properties in common. They are cross-grained, extremely hard and horn-like, and are considerably heavier than water even when thoroughly dry; the heart portion is infiltrated with a fragrantly scented gum-resin which gives the wood an oily appearance and feel.

The maximum density determined by the writer was 1.32 (about 82-1/2 lbs. per cubic foot) for Nicaraguan lignum-vitae. Krais (“Die Hölzer”) gives the range for dry wood of Guaiacum as 1.17 to 1.39, or from 73 to nearly 87 pounds per cubic foot. Other reliable figures of density are 1.248 (Laslett) and 1.33 (Beauverie). Stone (46) gives 89 pounds per cubic foot for Guaiacum sanctum and cites Sargent (40) as authority. This is an error, as the values given by Sargent are 0.9563 to 1.2736, average 1.1432. Boulger (5) uses the same figure as Stone.

Growth rings are often distinct, largely on account of color variations, though affected more or less by the relative abundance of pores and by the distribution of wood parenchyma. The woods are diffuse-porous and the pores, which vary in size from minute and indistinct to readily visible in some cases, are open in the sapwood but commonly filled with resin in the heart. They are often associated with or surrounded by parenchyma which may extend into fine tangential or irregularly spaced concentric lines. The rays are uniform and numerous but are too fine to be seen without a lens.

On the longitudinal surface, typically the tangential, very fine and regularly-disposed cross-lines or “ripple marks” are visible with the lens but not without it. These lines are at right angles to the axis of the tree and are not affected in direction or regularity by the criss-crossing of the fiber-layers. The number of these markings per inch of length averages about 250, which is so much greater than in any other wood that this feature alone is sufficient to establish the identity of the group (36, p. 259). These ripple marks are also characteristic of the inner bark (secondary phloem). (For structure of the bark of Guaiacum officinale see Joseph Moeller’s “Anatomie der Baumrinden,” Berlin, 1882, pp. 332-3.)

In a specimen (Yale No. 974) of the shrub Larrea divaricata Cav. (Zygophyllaceae) from Argentina the number of ripple marks is about 270 per inch. In this wood the ground mass is composed of small thick-walled fiber-tracheids with very abundant and prominent bordered pits. The rays are 1 to 12, mostly 6, cells high, uni-seriate or more commonly bi-seriate in the median portion; rather indistinctly storied. The wood parenchyma contains crystals some of which are large and conspicuous.

Porlieria

The representatives of this genus are shrubs or small trees growing in dry sub-tropical regions, and are not of commercial importance. Four species have been described, one belonging to a group of plants connecting the Mexican and Texas flora, two inhabiting the corresponding zone in Argentina and Chile, and a fourth, little known, in Bolivia.

This fourth species is described by Baillon (Adansonia, 10:315-16, 1872) under the name of “Guaiacum (Porlieria) microphyllum.” It was found in Bolivia. The leaves are only 1/5 inch long and 1/6 inch broad.

Porlieria angustifolia Gray (= Guaiacum angustifolium Engl.) is found in western Texas and adjacent regions of Mexico where it is common on the dry gravelly mesas of the valley of the lower Rio Grande. It is a small tree with very knotty branches, attains a height of 25 to 30 feet and a diameter of 6 to 8 inches, becoming reduced to a low shrub toward its eastern, northern, and western limits. “The hard and heavy yellowish-brown wood is called ‘guayacan’ about Saltillo, and used as a sudorific and in venereal diseases.” (12, p. 113.)

“The wood is exceedingly heavy, very hard, close-grained, compact, the open ducts smaller and less regularly distributed than in Guaiacum; medullary rays very thin, numerous; color, rich dark brown turning green with exposure, the sapwood bright yellow; sp. gr. 1.1101; ash 0.51; probably possessing medicinal properties similar to those of lignum-vitae.” (39, p. 29.)

Porlieria Lorentzii Engl. is a shrub or small tree on the Argentine steppes where it occasionally reaches a height of 25 feet and a diameter of 10 inches. It is covered with a thin dark gray scaly bark. The yellowish wood is very compact and fine-textured and makes a fairly satisfactory substitute for boxwood in turnery and carving. Its most common use is in the manufacture of domestic utensils, particularly spoons, and to the latter owes its vernacular name of “cucharero” (maker of spoons). The Indians use the wood, called by them “chukupi,” for making smoking-pipes (44, p. 378; 49, p. 105.)

The above is probably the species referred to by Castro (8, p. 77) as “guayacan blanco,” “chuchupi,” “chucupi,” or “chucarea,” though he gives the scientific name as P. hygrometrica. The following information is on his authority: The tree is found in Córdoba, Salta, Jujuy, Tucuman, Mendoza, San Luis, San Juan, and La Rioja, and is very abundant in the Andean provinces. In its better development it reaches a height of 13 to 20 feet and a diameter of 4 to 6 inches. The wood is hard and very strong and resilient. Specific gravity 1.11. It is susceptible of a high polish, has a high luster, and on account of its flexibility is in demand for canes and whipstocks. It is also used for turnery and carves with ease. In general carpentry it finds a place in the making of sash, doors, and blinds.

Porlieria hygrometrica R. & P. (= Guaiacum hygrometricum Bail.), is an ungainly shrub with sprawling branches and dropping leaves. When it “sleeps” it gives the appearance of being diseased or even in a dying condition. It was discovered by Ruiz and Pavon, first in Peru near Huanuco, where it was called “turucasa,” meaning “thorns fragile and not sharp” (referring to the stipular spines); afterwards in Chile where the Spaniards, who have imputed to it the sudorific property of guaiac, call it “guayaco,” also “palo santo.” Misled, no doubt, by the common name, Molina, who did not see the plant, has erroneously referred to it as Guaiacum officinale L. (13, pp. 465-6.)

Bulnesia

This genus, so far as known, is confined to South America. There are eight species, but only two, the “palo santo” of Argentina and the “vera” of Colombia and Venezuela, supply timber of commercial value. The others are low-branching shrubs on the dry foothills of the Andes Mountains in Argentina.

“Retama” or “Retamo”

In Patagonia the name “retamo” is given to Lippia juncea Sch. (38, p. 194).

Bulnesia Retamo Gris. is one of the latter group which sometimes develops into a short stout broom-like tree with a height up to 25 feet and a diameter of from 10 to 20 inches. According to Castro (8, pp. 131-2) the tree occurs in Misiones, San Luis, La Rioja, San Juan, Córdoba, and Catamarca. The tree is said to be of fine appearance and the branches, which are without leaves during the greater part of the year, are slender and pendulous. The gray-yellowish-green bark is from 7 to 8 mm. thick and has prominent corky lenticels and shallow furrows.

According to the same authority, the sapwood is yellowish-white, the heartwood dark-yellowish with veins of deeper color. The specific gravity is given as 0.917. The moduli of elasticity in bending, in kilograms per square millimeter, are: maximum 1,053; mean, 897; minimum, 780. The coefficients of resistance to rupture in bending, in kilograms per square millimeter, are: maximum, 12.25; mean, 7.50; minimum, 4.50.

The wood is “hard as iron” and is used to a limited extent for cross-ties, carpentry, posts, canes, tool handles, and also in the construction of furniture of “great durability and beautiful appearance.” The twigs and leaves have a place in medicine and the boughs are used by the mountaineers for thatching their huts. The charcoal from retamo wood is of a very high quality. Spegazzini (44, p. 397) states that the wood makes excellent fuel and occasionally supplies material for turnery.

“Palo Santo” or “Palo Balsamo”

This wood is supplied by Bulnesia Sarmienti Lorentz which is “indigenous to the Argentine province of Gran Chaco about halfway up the Rio Berjemo” (17, p. 453); Castro (8, p. 56) says it grows in Chaco, Salta, Tucamán, Jujuy, and Corrientes; it also occurs in Paraguay. It attains a height of 50 or 60 feet and a diameter of 40 inches (44, p. 376), has a straight bole with a very thin smooth gray bark, and in the interior of the Chaco generally rises above all of the other trees in the forest (49, p. 105). It is a tree of the dry regions and is for the most part in groups or patches yielding at most only a few hundred board feet per acre. Although the wood is well known to certain local minor industries making small cabinets and turnery, it is not obtainable in any considerable amount.

The sapwood is narrow and light-colored; the heartwood is usually deep-brown, often more or less greenish, and sometimes with alternate lighter and darker bands. The pores are small, thick-walled, numerous, and arranged in radial lines or groups, sometimes spreading or branching outward as in the late wood of white oak.

The specific gravity, as determined by the writer on two specimens, oven-dry, is as follows: All-heart specimen, 1.21; specimen with one-fifth sapwood, 1.18. According to Castro (8, p. 56) the sp. gr. is from 1.216 to 1.303. The moduli of elasticity in bending, in kilograms per square millimeter, are: maximum, 988; mean, 872; minimum, 827. The coefficient of resistance to rupture in bending, in kilograms per square millimeter, are: maximum, 14.07; mean, 10.81; minimum, 8.91.

The heartwood is thoroughly impregnated with resin of the nature of guaiac and contains in addition a small amount of essential oil which is fragrantly scented, somewhat suggesting sandalwood. This odor is quite pronounced upon heating and the wood is in local demand for incense in churches; hence the name “palo santo” (holy wood). It is used by the Indians in northern Argentina for firewood, torches, and the making of utensils for various purposes.

In Patagonia the name “palo santo” is given to Flotowia diacanthoides Less. (38, p. 192).

The name “palo balsamo” is a commercial term which has been in use since 1892, and refers to the oil content of the wood. By distillation the heartwood yields 5 or 6 per cent of this oil which is known to the trade as “oil of guaiac wood,” “oleum ligni guaiaci,” “Guajakholzöl,” or “essence de bois gaïac.”

The name “champaca oil” was later given to this same oil although it has not the slightest resemblance to the genuine champaca oil from Michelia champaca L. (Bericht von Schimmel & Co., Apr. 1893, p. 33). (17, p. 453.)

For many years the manufacture of this oil was confined to Germany and France, but during the war 2,000 pounds were distilled in New York. Since the sale is limited, this represents at least a five years’ supply. The wood is obtained in the form of logs, reduced to sawdust and fine chips, and distilled. Efforts to obtain the oil from the wood of Guaiacum were without success. Apparently no effort has been made to distill it from Bulnesia arborea.

Oil of guaiac wood is a viscous, heavy oil, yellowish in color, which at ordinary temperature gradually solidifies to a crystalline mass. The crystals are needle-shaped, sharply outlined, and characterized by a channel-like middle line. The solidified oil is white and of about the consistency of cold lard. The melting point is between 40° and 50°C. The odor of the specimens examined by the writer is mild, slightly pungent, and vaguely suggesting rose.

The following description of the properties and composition of the oil of guaiac wood is from Gildemeister and Hoffman (17, pp. 453-4). “The odor of the oil is very pleasant, being violet and tea-like. The specific gravity lies between 0.965 and 0.975 at 30°; the angle of rotation is -6° to -7° at 30°. The oil is soluble in 70 per cent alcohol. The saponification number found of an oil was 3.9, the ester number 2.4, and the acid number 1.4.

“The crystalline constituent of the oil is guaiac alcohol or guaiol (Wallach), a sesquiterpene hydrate C₁₅H₂₆O. Guaiol is an odorless body, crystallizing in large transparent prisms, and melting at 91°. It boils under ordinary pressure at 288°, at 10 mm. pressure at 148°. Its solution in chloroform is laevogyrate. With dehydrating agents a hydrocarbon C₁₅H₂₄ is formed, accompanied by an intensely blue substance. On boiling guaiol with acetic acid anhydride a liquid acetyl compound is produced which boils at 155° under a pressure of 10 mm. The odoriferous constituent of the oil has not yet been investigated.”

The New York manufacturers of oil of guaiac wood sell the oil in small quantities to perfumers, mostly in France, the price (1919) being about $2 an ounce. They inform the writer that they are not familiar with the use the perfumers make of it. According to Gildemeister and Hoffman (17, pp. 436, 454), it is used in the perfume industry for the purpose of producing a tea-rose odor and also as an adulterant of oil of rose.

“Vera” or “Maracaibo Lignum-vitae”

These names are applied to Bulnesia arborea Engl. (= Zygophyllum arboreum Jacq., = Guaiacum arboreum DC.) which occurs in the coastal region of Colombia and Venezuela. (See plate.) According to Sargent (40, p. 60) this species is “widely distributed through the northern countries of South America from Cartagena to Venezuela.” The fact that it was formerly, and occasionally is now, referred to as a species of Guaiacum accounts for some of the conflicting statements regarding the range of that genus. Flückiger says (14, p. 102): “This tree, occurring in New Granada (Colombia), has already been noticed (1571-1577) by Francisco Hernandez (Nova plantarum, animal. et mineral. Mexicanor. hist. Romae 1651, fol. 63) under the name of guayacan. He mentions its large umbels with yellow flowers, those of Guaiacum officinale, the ‘hoaxacan’ or lignum sanctum, being blue.”

Triana and Planchon (47, p. 362) describe this tree under the name of Guaiacum arboreum DC. and call attention to the differences in flowers and fruit between it and G. officinale. They report its occurrence in Colombia in the valley of the Magdalena up to an altitude of 2,600 feet above sea level, in Cartagena, the savannas of the valley of Uphar, Santa Marta; and in Estado Carabobo of Venezuela. The common names of “guayacan” and “guayacan polvillo” are given for this species and the wood is described as being of a dark yellow color tending to greenish and with an almost pulverulent fracture. There is indication of confusion of species here since the name “guayacan polvillo” is commonly applied to a certain species of Tecoma or Tabebuia (Bignoniaceae) and the pulverulent nature of the fracture would seem to refer to the lapachol compound which abounds in the wood of this and closely related species.

Stone (46, p. 18) describes the wood of Bulnesia arborea under the name of Guaiacum arboreum DC., and gives its source as Brazil, citing Miers as authority. The only other reference to the occurrence of this tree in Brazil that the writer has found is by Beauverie (3, p. 248) who apparently follows Stone and it seems probable that this information was incorrect, especially so in view of a statement by Huber (24, pp. 179-180) to similar effect.

The wood of Bulnesia arborea is known to the trade as “vera,” “vera-wood,” and “Maracaibo lignum-vitae.” The most common local name for it is vera. The variations in the color of the wood, attributed to the effect of site, give rise to the names “vera aceituno” (olive), “vera amarilla” (yellow), “vera azul” (blue), and “vera blanca” (white). “Guayacan” and “palosano” are synonyms for vera (1, p. 178). Another native name, a variant of vera, is “bera” or “berra.” Humboldt (25, pp. 7-8) says: “On leaving Cumana we enjoyed during the short duration of the twilight from the top of the hill of San Francisco, an extensive view over the sea, the plain covered with bera and its golden flowers; and the mountains of the Brigantine.” A foot-note referring to the tree reads: “Palo sano, Zygophyllum arboreum Jacq. The flowers have the smell of vanilla.”

The wood, along with true lignum-vitae, has recently been introduced in the brush-back trade under the fantastic name of “Congo cypress”!

Vera usually grows in places more favorable for its development than is the case of the other zygophyllaceous trees. Consequently it is often comparatively slender, straight-boled, and of rather good timber form. Sargent (40, p. 60) calls it a small tree, but all of the other writers refer to it as attaining large dimensions. Few reliable figures of size are available. Sievers (43, p. 194) says that it reaches a height of approximately 100 feet in the Maracaibo region. The present writer has seen logs of this species in New York, transshipped from Curaçao, that were from 14 to 20 inches in diameter and from 8 to 12 feet long. They were smooth, straight, cylindrical and free from knots, indicating that they had come from rather tall trees. The bark was dark gray, smoothish, with longitudinal wrinkles. The bark of a smaller stem was very thin, of a gray-greenish color and showed fine longitudinal wrinkling, crossed at right angles with numerous fine white lines.

Mr. H. M. Curran supplies the following information regarding this tree in Venezuela: “Vera is a common tree of the dry foothills lying between Porto Cabello and the Lake Maracaibo. It does not extend into the extremely dry coastal hills and sand dune areas, but where a little more moisture and better soils are found it is often a very prominent feature in the vegetation. Perhaps four or five trees per acre may be found over considerable areas though the stand would probably be less than 1,000 board feet per acre. The tree as commonly met with is from 40 to 50 feet in height, slender, with a rather small branched crown and is fairly straight, though many individuals are twisted. The tree seldom makes a clear length of more than 15 or 20 feet. The flowers are bright yellow, and the tree is quite ornamental when in bloom. The fruits following the fall of the flowers are rather membranaceous winged pods. The wood is hard, very durable, and is commonly used for fence posts, telegraph poles, and durable construction in general.”

The wood of vera has many technical properties in common with the true lignum-vitae (Guaiacum). In the specimens examined by the writer the heartwood is more or less striped and banded, and varying in color from light olive-green to chocolate-brown. The surface of fresh wood often turns dark green upon exposure to the air and sun. The sapwood is mostly thin and is light yellow except near the heart where the vessels become green upon oxidation of their contents, thus giving a finely striped effect. Generally the color is lighter than in Guaiacum. One finds the same arrangement of pores as in Bulnesia Sarmienti except that the radial lines are usually narrower and not so inclined to branch. The specific gravity of the heartwood, as determined by the writer on oven-dry material, varies from 1.11 to 1.21. J. Martinex Espino (see 1, p. 178) gives 1.14 as the average density. The heartwood is impregnated with the mildly scented resin typical of the woods of this family.

The heartwood is very durable under exposure and will last indefinitely in the ground. Mr. H. M. Curran found among the ruins of an old Spanish fort on the tip of Araya Peninsula, Venezuela, a pole which was in perfect preservation after some 300 years. A specimen of this wood was examined by the writer and identified as the heartwood of Bulnesia arborea. (For features distinguishing the woods of Bulnesia and Guaiacum see page 19.)

Guaiacum

This genus, the source of the true lignum-vitae of commerce, is well distributed over the islands and coastal regions of tropical North America. The range in South America seems to be limited to the northern fringe of coast and adjacent islands. Most of the commercial timber is supplied by the West Indies;--Cuba, Haiti, Dominican Republic, Jamaica, and the Bahamas. Considerable material is also obtained from the west coast of Nicaragua.

Description of Species

At least six species are recognized by botanists but very little reliable information is available regarding their respective ranges. There are two species in the West Indies, namely, Guaiacum officinale L. and G. sanctum L. The latter is a small evergreen tree sometimes reaching a height of 30 feet with a small and stout trunk, rarely 12 inches in diameter, clothed with a thin pale or white scaly bark. The slender pendulous branches are enlarged at the nodes and somewhat furrowed. The ovoid, five-cornered fruit is greenish-yellow to bright orange, the seeds dark brown or black and covered with a scarlet exocarp. It is often cultivated for decorative purposes on account of the beauty of its flowers and foliage. It grows naturally in southern Florida, “abundantly on Upper Metacombe and Lignum-vitae Keys and less commonly on Lower Metacombe and Umbrella Keys” (40, p. 63), and is the only representative of the genus reaching the United States. The species occurs throughout the West Indies and, according to Vail and Rydberg (48, p. 106), grows naturally in Yucatan. It has never been of great commercial importance because of its small size and is still less so now than formerly. Flückiger (14, p. 101) says of it: “It is found in southern Florida, the Bahama Islands, Key West, Cuba, San Domingo (including the part called Hayti), and Puerto Rico, and is certainly the source of the small but excellent lignum-vitae exported from the Bahamas as well as some of that shipped from Hayti.”

For key to these species see Vail and Rydberg (48, p. 105).

Varietal forms of G. sanctum exist in Haiti, but have not been described. According to Mr. C. D. Mell, one of these produces a large timber tree, the bera or so-called bastard lignum-vitae of Haiti.

Sargent (40, p. 63) gives maximum diameter of trunk as 2.5 to 3 feet.

The specific gravity of oven-dry wood of this species from Florida, as determined by Sharples (see 39, pp. 268-9), varies from 0.9563 to 1.2736, average 1.1432. The variations are in part due to the presence of more or less sapwood in some of the specimens. The specific gravity, oven-dry, of a specimen from Florida was found by the writer to be 1.09 for the sapwood portion and 1.19 for the heartwood. The sapwood of Guaiacum sanctum is usually thicker than in G. officinale.

In longitudinal compression, the ultimate strength in kilos of two specimens of Florida wood was found by Sharples (see 39, p. 420) to be 11,930 and 11,648, respectively. These values were somewhat in excess of those for the best specimens of hickory but were materially exceeded by some pieces of Osage orange, black locust, and some less common woods. In resistance to indentation the wood of Guaiacum sanctum is given first rank (see 39, p. 253) among 405 woods tested, and is far above any of the common woods of the United States.

Guaiacum officinale is a low or medium-sized evergreen tree with a thick bole often 10 to 12, occasionally 18 to 20, inches in diameter. Its branches are crowded and flexuose and the pinnate leaves are leathery. The fruits are two-cornered and yellowish, bearing seeds light to dark brown with a cream-colored exocarp. Its range includes all of the West Indies and the northern coast of South America, especially Venezuela and Colombia. Schomburgk (42, pp. 850, 1,012) says it is cultivated in gardens along the coastal region of British Guiana and also grows in the forests along the Essequibo, where it reaches tree size. No other reference to its occurrence in British Guiana has been found. According to Vail and Rydberg (48, p. 106) the species grows naturally in Panama, and Harshberger (21, p. 664) mentions it as occurring in Honduras.

Oviedo (see 14, p. 101), who landed in America in 1514, mentions this tree, under the name of “guayacan,” as a native. (This should dispose of the claim of a Brazilian botanist (7, p. 81) that Guaiacum officinale L. was introduced into San Domingo from the Matto Grosso by the Spaniards in 1508, and thereafter considered native there). Oviedo appears to have been aware of two species, one of which he found in Espanola (San Domingo) as well as Nagranda (Nicaragua), and the other in the island of Sanct Johan (Porto Rico), whence it was called “lignum sanctum.” This name is still in use, particularly for the wood of Guaiacum sanctum.

Four Mexican or Central American species of Guaiacum are described by Vail and Rydberg (48, pp. 106-7), but very little is available regarding their commercial importance and range. G. guatemalense Planch. is said to be a small tree about 15 feet high with stems clothed with somewhat corky bark. The flowers, which are azure blue, appear before the new leaves; the fruit is reddish or orange, the seeds reddish-brown. The type was collected on the hot plains of Zacapa, Guatemala, and nothing further is known of its range.

Guaiacum Planchoni A. Gray is said to be a much branched shrub, 6 to 10 feet high, with grayish corky bark, leaves crowded or fascicled on short modified branchlets; flowers solitary. The type was collected between Tehuantepec and the Pacific Ocean, Oaxaca.

Guaiacum Palmeri Vail is, according to the same authorities, a shrub or possibly a small tree, with leaves fascicled as in the preceding. The fruit is yellowish-green, leathery, with seeds covered with a dark-red (?) fleshy exocarp. The type was collected at Guaymas, Sonora.

Guaiacum Coulteri A. Gray produces wood of value, though to what extent is undetermined. This tree is known to occur all along the western part of Mexico from Sonora to Oaxaca and it is possible that the commercial lignum-vitae of Nicaragua and the east coast of Mexico is supplied by this species. According to the botanists the tree is small, often reduced to a shrub, with clustered blue flowers and with greenish fruit containing brown seeds covered with a pale yellowish aril.

Hemsley (22, p. 159) suggests the possibility of this and G. guatemalense Planch. being the same species, but the material at his disposal was insufficient to decide the question.

In 1913, Dr. H. N. Whitford made an examination of the forest on Maria Magdalena Island, the middle one of the Tres Marias group off the coast of Tepic, Mexico. He found a tree called “guayacan” which was afterward identified as Guaiacum Coulteri. In a manuscript report he says:

“This species is probably the lignum-vitae of commerce. It occurs growing very scattered with the ‘palo prieto’ and on the flats near the mouths of the arroyos. The trees are mostly small, between 8 and 12 inches in diameter, yielding logs from 6 to 10 feet in length. One tree was 24 inches in diameter yielding a log only two feet long. It had three branches 8 inches in diameter and 6 feet long that would make good logs. The forests on the main coast are said to produce trees much larger than those on the island. Guayacan is very hard, very durable and very heavy. It is dark greenish-brown in color with concentric rings of nearly black. It is very fine-grained.”

Minute Anatomy of the Wood of Guaiacum

The pores are circular or elliptical and are irregularly distributed, being sometimes abundant and sometimes few and scattering. Usually no definite arrangement can be noted, but occasionally they are in echelon and in some cases a tendency to a ring-porous structure has been observed. There may be considerable difference in the size of the pores in the same specimen while in others they are fairly uniform. In a piece of Cuban lignum-vitae, 14 of the largest pores were found to have an average size of 0.15 × 0.11 mm.; the maximum was 0.18 × 0.14 mm. In a specimen from Nicaragua the pores were nearly all small, the largest measuring about 0.10 × 0.08 mm. The walls in both cases were about 0.01 mm. thick.

The vessel segments, wood fibers, wood parenchyma strands, and the rays are in horizontal seriation. The bordered pits between contiguous vessels are small, very numerous, and with rounded or hexagonal outlines; the pits between the vessels and rays are small, numerous, and half-bordered. The wood fibers are very thick-walled, very small, short, crowded together without any definite arrangement, and provided with numerous weakly bordered pits. The vessel segments are mostly 0.09 to 0.10 mm. in length, with simple perforations throughout, without tyloses, but with abundant resin (in heartwood) which dissolves readily in alcohol. The rays are from 1 to 8, mostly 5 or 6, cells high and either uni-seriate throughout or two cells wide in the middle portion. The individual cells are very small, thick-walled, sometimes containing crystals, and commonly resinous. Wood parenchyma is present in varying amount in association with the vessels, or diffused, or in tangential lines of irregular length or sometimes in concentric bands several cells wide apparently limiting growth rings. The variations in the amount and arrangement of the parenchyma are very noticeable, not only in different woods but also in different parts of the same specimen.

Distinguishing Features of the Woods of Guaiacum and Bulnesia

Guaiacum Bulnesia

Pores irregularly disposed. Pores in radial arrangement. (See (See opposite page.) opposite page.)

Pores often widely variable Pores small and fairly uniform in in size; largest sometimes size; not individually distinct visible without lens. without lens.

Pores mostly circular or oval. Pores often angular in outline.

Parenchyma paratracheal and Parenchyma paratracheal and metatracheal; also often terminal diffuse; indistinct with lens. in fine lines distinct with lens.

Crystals present but not abundant Crystals very abundant in wood in wood parenchyma and rays. parenchyma and rays.

Rays mostly uni-seriate; Rays commonly 2-seriate sometimes 2-seriate in middle (occasionally 3-seriate) in middle portion. portion.

Essential oil not known to be Essential oil known to be present, present. at least in one species.

Woods of the two genera are alike in being very dense, fine-textured, cross-grained; dark brown or greenish in color with oily appearance and feel; mildly and pleasantly scented when warmed; containing guaiac resin with characteristic color reactions. Woods with very fine and uniform ripple marks, invisible without lens, averaging about 250 per inch of length. These ripple marks are likely to be absent in small twigs (0.5 cm. or less) such as one commonly finds in herbarium material. The characteristic alternating or fine-roe grain was not found in stems or twigs less than 1 cm. thick. The interlocked grain is not due, as sometimes supposed, to the crossing of true right and left hand spirals around the stem, but to a weaving back and forth of the fiber layers in an irregular “lazy-S” manner up and down the trunk.

Check List of Common Names

Guaiacum officinale: Lignum-vitae (U. S.; general trade); guaiacum-wood (England); holy wood, wood of life, Indian wood (Lit.); guayacan, guaiacan, guayakan (Spanish); hoaxacan, lignum sanctum, guayacan blanco (Porto Rico); guayacan negro, guayacan prieto, palo santo (Cuba); gayac jaune vert (Martinique); bois de gaïac or bois de gayac, bois sant (Fr.); Pockholz, Guaiacholz, Guajak, Guajakholz, Franzosenholz, Lignum Sanctum-holz (Ger.); guaiaco nero, legno santo, legno benedetto, legno nefritico, legno di guaiaco (Ital.); pokhout (Dutch); guaiaco (Port.); “Congo cypress” (Brush-back trade).

Guaiacum sanctum: Lignum-vitae (America; general); Bahama lignum-vitae (Eu. trade); palo santo, lignum sanctum, lignum guaici (Spanish); vera, bera (Haiti); vera amarilla, vera prieta, guayacancillo (Cuba); ironwood (Florida); guaiaco banco, legno santo, legno benedetto (Ital.). The wood of this species is often not distinguished from the foregoing and the same names may be used for both.

Guaiacum spp.: Lignum-vitae (Trade); guayacan, palo santo (Mex.).

Bulnesia arborea: Vera, vera aceituna, vera amarilla, vera azul, vera blanca, bera, berra (Venezuela, Colombia); Maracaibo lignum-vitae, vera-wood (Trade); guayacan, palo sano (Colombia); gayac de Caracas (Fr.); Vera-holz (Ger.); “Congo cypress” (Brush-back trade).

Bulnesia Sarmienti: Palo santo (Argentina); palo balsamo (Trade); palo santo negro (Paraguay); páo santo (Port.).

Bulnesia retamo: Retama, retamo (Argentina).

Porlieria angustifolia: Guayacan.

Porlieria Lorentzii: Guayacan blanco (Argentina); cucharero, chucarea, chukupi, chuchupi, chucupi (Indian names, Arg.).

Porlieria hygrometrica: Guayaco, palo santo (Chile); turucasa (Peru).