リュウキュウマツ [Japanese]; Luchu pine, Ryukyu Island pine.
Pinus luchuensis is the Japanese representative of a group of three closely related taxa: Pinus luchuensis of Japan, Pinus taiwanensis of Taiwan, and Pinus hwangshanensis of mainland China. Various authors have treated P. taiwanensis and P. hwangshanensis as synonymous with, or as varieties or subspecies of, P. luchuensis. All three taxa are morphologically similar, but distinct, and they are here treated as separate species, although they could also be called subspecies of P. luchuensis.
Pinus luchuensis was described from the Ryukyu Islands (Li 1975).
"A large evergreen tree. Leaves two in a fascicle, 8-15 cm. long, dark green, semicircular in cross section, with 2 vascular bundles and 2-3 medial resin ducts. Matured cones ovoid, 4-5 cm. long; scales armed. Seeds winged; wings lanceolate, about double in length as seeds. Trunk bark grayish brown, deeply fissured, furrows about 1.0 cm. in depth, 1.5-4.0 cm. across; ridges flattened, broken into flaky plates; lenticels inconspicuous; outer barks about 0.2-1.5 cm. thick, hard and brittle, more or less ligneous, with a brown cross section; newly formed periderm milky white; inner barks 2-5 mm. thick, pale yellowish white, finely fibrous, gumming pale yellowish, transparent resin after cutting; cambium and newly formed phloem colorless,somewhat transparent, rather thick. Freshly cut sapwood pale apricot yellow, wood rays inconspicuous" (Liu 1970).
Liu (1970) and Li (1975) note that P. luchuensis, compared to P. taiwanensis, has longer needles (12-16 vs. 8-11 cm), fewer resin ducts (2-3 vs. 4-7); shorter cones (4-5 vs 6-7 cm); thinner bark; and different inner bark coloration (pale yellow-white vs. pale red-white).
Japan: Okinawa, Ryukyu Island; near sea level; in habitats ranging from large pure stands to broadleaf-conifer forest to subalpine meadow (HAST Database, Li 1975, Liu 1970). Hardy to Zone 9 (cold hardiness limit between -6.6°C and -1.1°C) (Bannister and Neuner 2001).
Not seen. Some specific location data (HAST Database) records this collection: Okinawa, 128° 15'50"E, 26°52'17"N, 100 m. Margin of forest. A tree ca. 6-7 m tall.
Mayr, H. 1894. Über die Kiefern des japanischen Reiches. Beihefte zum Botanischen Centralblatt 58:148-151.
Last Modified 2017-12-29