Acta Phytotaxonomica et Geobotanica

The writer noticed that there are two forms of Juniperus communis var. nipponica W_<ILSON> (J. nipponica M_<AXIM>.) in Japan. One is called Northern Form, and the other Southern Form. The difference of the two is mainly based upon the characters of leaves, as following lines. Northern Form : leaves 1-1.2 mm wide, 0.8 mm thick; stomatous groove on the upper surface 0.2-0.4 mm wide, 0.2-0.35 mm deep; shape of cross-section of leaf shown in (Fig. 1, A-B and Fig. 2, A). Southern Form : leaves 1.7-2 mm wide, 0.7-0.8 mm thick; stomatous groove on the upper surface 0.7-0.9 mm wide, 0.1 mm deep; shape of cross-section shown in Fig. 1, C-D and Fig. 2 B. The distribution areas of the two forms are also separated each other, and a border line is drawn detween lat. 37゜ and 38゜ N. (Fig. 4). It is supposed that Juniperus nipponica M_<AXIM>. is referable to the Northern Form, therefore the writer proposed a new varietal name for the Southern Form.

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1. The author investigated the pollen morphology of 121 species of Ericaceae, belonging to 24 genera (Japan 16 g. 82 sp., Kuril Arch. 9 g. 9 sp., Saghalien 7 g. 8 sp., Korea Pen. 2 g, 6 sp., Ryukyu Arch. 3 g. 5 sp., Formosa 4 g. 14 sp.) and 18 species of Pyrolaceae, belonging to 4 genera (Japan 4 g. 10 sp., Kuril Arch. 1 g. 1 sp., Saghalien 1 g. 1 sp., Korea Pen. 1 g. 2 sp., Formosa 2 g. 4 sp.). 2. The diameter of the tetrads varies from 20 μ in Arcterica nana (Fig. 82) to 77 μ in Rhododendron pentaphyllum (Fig. 40). 3. Rhododendron boninense (Fig. 74) and Chimaphila umbellata (Fig. 140) have the loosely attached tetrads and represent intermediate forms between tetrads and single grains. 4. The fine structure of the pollen wall and the viscin strands were investigated.

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The Species problem was discussed from view point of the chemical constituents and a definition of Species by the combination of morphology and physiology was stated. The meanings of chemical constituents to the plant systematics were further explained.

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The present paper was intended to describe further details on the genus Comastoma established by the writer in 1961. W_<ETTSTEIN> (1896) separated this group from the section Amarella of Gentiana as a distinct section, giving the name Comastoma. This treatment had been taken up by many authors either under Gentiana as W_<ETTSTEIN> (1896) proposed originally or under Gentianella as S_<MITH> did (1945, in H_<YLANDER>) until 1956, when A. and D. L_<OVE> transferred it to Lomatogonium, giving emphasis on its chromosome number. As has been stated by A. and D. L_<OVE> (1956 & 1961), the haploid number of chromosomes for both Lomatogonium rotatum and so-called Gentianella tenella is actually 5, but the form of stigma, the number of vascular bundles in each corollalobe and the position and shape of fimbriated scales at corolla-orifice draw a clear cut line of demarcation between both genera. G_<ILLETT> (1957), on the other hand, considered the present genus to be a subgenus of Gentianella ; in the genus Gentianella, however, the fimbriated scales at corolla-orifice are run through by vascular bundles and the epipetalous gland is always only one, not in pairs as in Comastoma. The section Comastoma of Gentiana established by W_<ETTSTEIN> thus forms a distinct group differing from Gentiana, Gentianella and Lomatogonium. In the light of the above findings, the present writer established the new genus Comastoma, to which belong about 7 species from the circumboreal or alpine region of the Northern Hemisphere. From the point of view of phylogeny, the present genus seems to have sprung out from the common ancestor, Pregentiana in a line quite separate from that of Gentiana (Fig. 5).

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