Pinus merkusii Jungh. & de Vriese MAP 39 
Merkus pine 
Pinus merkusw Jungh. & de Vriese in de Vriese, 
Pl. Nov. Ind. Bat. 5, t. 2. 1845. 
Pinus merkusii ranges from eastern Burma, northern 
Laos, northern Vietnam, and the island of Hainan south to 
Cambodia, southern Vietnam, and the island of Sumatra, and 
east to Luzon and Mindoro in the Philippine Islands. This 
species is the only member of the genus that extends south 
of the Equator. It reaches its southern limit at about 2° S. 
latitude on Sumatra. The distribution of P. merkusii is still 
not completely known, especially on the Asian mainland. Its 
natural occurrence on the island of Hainan is questionable; 
Merrill (1927) indicates that it may have been planted there, 
but both Hosokawa (1940) and Wu (1956) show Hainan as 
part of the natural range of this species. P. merkusii grows 
at low elevations throughout its range, and in many areas is 
associated with and replaced elevationally by P. insularis. 
These two closely related species may hybridize on Luzon 
(see P. insularis) . 
Sources: 
Published—Bui 1962; Philippine Islands, Bureau of For- 
estry, 1935 (Mindoro); Burkill 1924 (Burma, Thailand); 
Chevalier 1944 (Vietnam); Ferrars 1875 (Burma); Luytjes 
1924 (Sumatra); Maurand 1943; Merrill 1927 (Hainan); 
Royal Forest Department, Thailand, 1962 (Thailand) ; Ryan 
and Kerr 1911 (Thailand); P. Singh 1913 (Burma); van 
Steenis 1958 (Sumatra); Suvatabandhu 1961 (Thailand); 
Vidal 1960 (Laos); Wilson 1926 (Burma, Thailand) . 
Unpublished—W. S. Astle to N. T. Mirov 1961 (Cam- 
bodia); N. T. Mirov 1961 (Luzon, Sumatra); M. Schmid to 
N. T. Mirov 1961 (Vietnam); Silviculturist, Burma, 1963 
(Burma) . 
SUBSECT. AUSTRALES Loud. 
Pinus palustris Mill. MAP 40 
longleaf pine 
Pinus palustris Mill., Gard. Dict. Ed. 8, 
Pinus No. 14. 1768. 
Longleaf pine is limited to the Coastal Plain of south- 
eastern United States from southeastern Virginia to central 
Florida and west to eastern Texas. It hybridizes in nature with 
at least two of its principal associates, Pinus taeda (Chapman 
1922) and P. elliottii (Mergen 1958). 
Pinus taeda L. MAP 41 
loblolly pine 
Pinus taeda L., Sp. Pl. 1000. 1753. 
Loblolly pine ranges through the Coastal Plain and Pied- 
mont of eastern and southeastern United States from Dela- 
ware south to central Florida, west to eastern Texas, and 
north in the Mississippi Valley to southeastern Oklahoma, 
Arkansas, and southern Tennessee. It is associated with sev- 
eral related species, and is believed to hybridize in nature 
with at least four of them—Pinus palustris (Chapman 1922) 
P. echinata (Zobel 1953), P. serotina (Wenger 1958), and P. 
rigida’. 
Additional source: 
Published—Bethune 1963 (Fla.). 
6 Committee on Southern Forest Tree Improvement Newsletter IV (1). 
May 1955. (Processed) . 
Pinus echinata Mill. MAP 42 
shortleaf pine 
Pinus echinata Mill., Gard. Dict. Ed. 8, 
Pinus No. 12. 1768 
Shortleaf pine extends from Long Island, New York, and 
New Jersey to Pennsylvania, southern Ohio, southern Illinois, 
and southern Missouri, south to eastern Oklahoma and east- 
ern Texas, and east to northern Florida and Georgia. The 
most widespread of the southern pines, this species occupies 
large areas of Coastal Plain, Piedmont, and mountains from 
the Appalachians to the Ozarks. It crosses naturally with at 
least two associated pines, Pinus rigida (Austin 1928) and P. 
taeda (Zobel 1953). 
Additional sources: 
Published—Aughanbaugh 1950 (Pa.); Haney 1955; Lim- 
ing 1946 (Mo.); Perry 1924 (Pa.); Shafer and Chisman 1957 
(Paine 
Pinus glabra Walt. MAP 43 
spruce pine 
Pinus glabra Walt., Fl. Carol. 237. 1788. 
Spruce pine is confined to the Coastal Plain of southeast- 
ern United States from South Carolina to northern Florida 
and west to southeastern Louisiana. A minor constituent of 
the pine forests, it is associated with Pinus taeda, P. elliottit, 
and others. 
Pinus rigida Mill. MAP 44 
pitch pine 
Pinus rigida Mill., Gard. Dict. Ed. 8, 
Pinus No. 10. 1768. 
Pitch pine ranges from central Maine to New York, ex- 
treme southwestern Quebec, and extreme southeastern On- 
tario, south to Pennsylvania, Ohio, and Delaware, and south 
in mountains to eastern Tennessee, northern Georgia, and 
western South Carolina. From near sea level northward, this 
species extends southward into higher altitudes along the 
entire length of the Appalachian Mountains. It often grows 
on poor sites, and is the characteristic tree of the pine barrens 
of New Jersey. 
It is associated with several related pines in the southern 
part of its range, and is thought to cross in nature with Pinus 
echinata (Austin 1928) and P. taeda’. Its closest relative, 
however, is P. serotina. These two very similar pines inter- 
grade in Delaware’ and southern New Jersey (Clausen 1939), 
but it is uncertain whether this intergradation is due to hy- 
bridization or to incomplete divergence of the two. 
Additional sources: 
Published—Grandtner 1961 (Que.); Illick and Aughan- 
baugh 1930 (Pa.); Rouleau 1955 (Que.). 
Unpublished—T. C. Brayshaw and A. E. Porsild 1964 
(Canada). 
Pinus serotina Michx. MAP 44 
pond pine 
Pinus serotina Michx., Fl. Bor.-Amer. 2: 205. 18053. 
Pond pine is restricted to the Coastal Plain of south- 
eastern United States from southern New Jersey and Delaware 
south to central and northwestern Florida and central Ala- 
bama. 
It is thought to cross naturally with one of its commonest 
associates, Pinus taeda (Wenger 1958). At the northern end 
of its range it overlaps and intergrades with P see J 
rigida). 
7 Committee on Southern Forest Tree Improvement Newsletter TV (1). 
May 1955. (Processed) . 
