Base of wing-blade thin or slightly thickened. Cones dehiscent at maturity. Pits of ray-cells large X. Lariciones Pits of ray-cells small XI. Australes Cones serotinous, pits of ray-cells small XII. Insignes Base of wing-blade very thick XIII. Macrocarpae HAPLOXYLON Bases of the bracts subtending leaf-fascicles not decurrent. Staminate flowers not sufficiently developed in the bud to be apparent. Spring-shoots uninodal. Fibro-vascular bundle of the leaf single. Cone symmetrical, of relatively fewer larger scales, its tissues softer. Bark-formation late, the trunks of young trees smooth. Wood soft and with little resin, of uniform color and with relatively obscure definition of the annual rings. Tracheids of the medullary rays with smooth walls. All the species of this section, except P. Nelsonii, have deciduous fascicle-sheaths. There are but two species of Diploxylon with deciduous sheaths, P. leiophylla and P. Lumholtzii, both of them easily recognized. The deciduous sheath, therefore, is an obvious and useful means for recognizing the Soft Pines. On the characters of the fruit and the wood Haploxylon can be divided into two subsections. a. Cembra Umbo of the cone-scale terminal. b. Paracembra Umbo of the cone-scale dorsal. =Cembra= Umbo of the cone-scale terminal. Scales of the conelet unarmed. Leaves in fascicles of 5, the sheath deciduous, the two dermal tissues distinct, the hypoderm-cells uniform. Pits of the cells of the wood-rays large. Seeds wingless. Cones indehiscent I. Cembrae. Cones dehiscent II. Flexiles. Seeds with an adnate wing III. Strobi. =I. CEMBRAE= Seeds wingless. Cones indehiscent, deciduous at maturity. In this group of species there is no segregation of sclerenchyma into an effective tissue. The cones are inert under hygrometric changes and may always be recognized in herbaria by their persistent occlusion and soft tissues. The seeds are released only by the disintegration of the fallen cone. There is, however, a vicarious dissemination by predatory crows (genus Nucifraga) and rodents. Leaves serrulate, their stomata ventral only. Cones relatively larger, the apophyses protuberant 1. koraiensis. Cones relatively smaller, the apophyses appressed 2. cembra. Leaves entire, their stomata ventral and dorsal 3. albicaulis. 1. PINUS KORAIENSIS 1784 P. strobus Thunberg, Fl. Jap. 275 (not Linnaeus). 1842 P. koraiensis Siebold & Zuccarini, Fl. Jap. ii. 38. 1857 P. mandschurica Ruprecht in Bull. Acad. Sci. St. Pétersb. xv. 382.