Common Trees of Puerto Rico and the Virgin Islands

CALTROP FAMILY (ZYGOPHYLLACEAE)
Key to the 2 native species, both illustrated (Nos. 93-94)
A. Leaflets mostly 4, sometimes 6; fruits niostly flattened, heart-shaped at apex-93.
Ah. Leaflets mostly 6-10; fruits deeply 5- or &angled or winged, pointed at apex-.
ffiiaiacum oflcinale.
ffuaiacrrnt aanctum.
93. GuayacPn, common lignumvitae Guaiacum officinale L,
A handsome small evergreen tree with a dense
rounded crown and dark green foliage, easily recognized
by : (1) light brown bark smoothis11 and
mottled, peeling off in thin scales; (2) opposite
even pinnate leaves with mostly 4 or 6 stalkless,
oblique, broadly elliptic or obovate leathery leaflets;
(3) several to many deep to pale blue flowers
with 5 petals minutely hairy on the outer surface,
spreading starlike %-7/8 inch across in showy terminal
and lateral clusters shorter than the leaves;
and (4) flattened orange:brown capsules 3/q inch
long and broad, heart-shaped and slightly winged,
attached at narrowed end.
A tree 15-30 feet high, with a short trunk 4-18
inches in diameter. The bark scales are 1-2 inches
across and upon falling expose smoothish graybrown
spots beneath. Inner bark is light brown
and bitter. The green twigs, turning to gmy, have
enlarged ringed nodes and are much brnnched and
widely forking.
Leaves are 11/24 inches long, with green axis
and at base paired minute hairy scales (stipules)
which shed early. I~aflets are %-2 inches long
and inches wide, rounded or sometimes
blunt-pointed at both base and apex, broadest on
the side ton-ard base of leaf, slightly thickened and
often turned under at edges, Ilairless, and dark
green or olive green on both sides, slightly shiny
above. The lowest pair of leaflets is at the base of
axis beside the twig, while the pair of leaflets at
apex is largest.
Many prett faintly fragrant flowers me
clustered toget r' ~er (umbellike) on slender minutely
hairy stalks 3/8-1 inch long. There are 5 broad
rounded finely hairy sepals near1 1/4 inch long;
5 spreading deep to pale blue peta i" s nearly % inch
durable and very resistant to decay. It is very
resistant to attack by dry-wood termites, but the
sapwood is susceptible.
The self-lubricating resinous wood is so valuable
that it is sold by weight, though not now of commercial
importance in Puerto Rico. It is famed
for its specinl use in bearings and bushing blocks
for propeller shafts of steamshi s. It serves also
for pulley sheaves, deadeyes, an cf' as a replacement
for metal bearings in roller mills. Other uses inc111de
bandsam guides, awning rollers, furniture
casters, mallets, bowling balls, and turned novelties.
Under the name lipurnvitae (Latin for wood
of life), the extract of this wood formerly was
offici,z! in medicine as a stimulant and to increase
perspiration. Earlier it was thought to be a cure
for various diseases, having been introduced in
Europe about 1508. Also employed medicinally
was guaiac resin, which exudes from bark and sapwood,
reddish brown in color but changing to blue
or blue green.
The trees occasionally are planted as orna-
~nentnls for the masses of blue flowers, which are
rare in the tro ics, and for the handsome dark
green foliage. &owever, their growth is slow, so
slow that forest plnntings in Puerto Rim by the
Forest Service have been discontinued in favor of
other species. Bees visit the flowers.
Forests, thickets, and pastures in the dry coastal
and dry limestone regions of Puerto Rico from
GII~ ama to Cabo Rojo. Also in Culebra, Vieques,
St. Zroiroix, St. Thomas, and St. John. Re orted to
be nearly exterminated on Virgin Islan B s except
in cultivation.
PUBLIC mn~s~.--G~nica.
long, narrowed at base and rounded at apex, mi- MUNIICIPALJTIE-S
WHEILE ESPECIALLY COMMON.-
nutely haiiy on outer surface; 10 stamens about 12,66.
9i6 inch long, with blue filaments and yellow RANGE-JVest Indies from Bahamas and Greatrultbers;
and stalked pistil j/4 inch long, with flat- er Antilles to Bfartinque in Lesser Antilles and in
tened usually 2-celled ovary and pointed style. Bonnire? Cura~ao, and Aruba. Also in Panama,
The flattened capsules minutely pointed at the Colombia, Venezuela, and British Guiana. Plant-
I~eart-shaped apex are green when immature, turn- ed in southern Florida, Bermuda, Trinidad and
ing orange brown. They split open to discharge Tobago, Surinam, and elsewhere in tropical
2 or 1 seed 1/2 inch long, brown with a red fleshy America.
covering (aril) . Flowering and fruiting from OTI ir:~ COBI ;\ION NAMES.-payaco (Puerto
earl spring to fall. Rim) ; lignumvitae (Virgin Islands) ; 8yacitn
~ inarrow e sa wood is pale yellow. Henrtlrood (Spanish) ; palo snnto (Cuba, ~enezuelar yayais
dark greenish 6 rown or nearly black. Lignum- cln neFo (Cuba) ; payacbn de playa, guay~bn
vitae is one of the heaviest commercial woods (spe- colombitmo, guayaco (Colombia) ; lignumvitne,
cific c,~:ivity about 1.2-1.3). It is extremely hard, common lignumvitae (United States, English,
of wry fine uniform texture, with highly inter- commerce) ; gai'ac (French, commerce) ; gaiac
locked grain, growth rings clearly defined, and franc, gai'c m&le (Haiti) ; bois saint (Martinique) ;
characteristic oily feel caused by the unique resin wayad, pokhout (Dutch West Indies) ; guainco,
content. The mood is difficult to season and work pau santo (Brazil).
but takes a fine polish. The heartwood is very The generic name is also spelled Guajacum.
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