2020 年 71 巻 2 号 p. 163-169
A new peloric form of Cephalanthera erecta (Thunb.) Blume (Orchidaceae) is reported from Hokkaido, Honshu, and Shikoku, Japan. Cephalanthera erecta f. pelorica Hiros. Hayak. & Suetsugu has an inconspicuous lip and stigmas positioned at the apex of the column. The flowers of C. erecta f. pelorica resemble those of the probable peloric form of C. erecta (i.e., C. erecta var. oblanceolata N. Pearce & P. J. Cribb, C. nanlingensis A. Q. Hu & F. W. Xing) and C. longifolia (L.) Fritsch. f. conformis Suetsugu & Hiros. Hayak. However, C. erecta f. pelorica can be distinguished from C. erecta var. oblanceolata, which has a swollen organ on the abaxial surface of the column apex (vs. no swollen organ); C. nanlingensis, which has two staminodes (vs. five staminodes), and C. longifolia f. conformis, which has elliptic, coriaceous leaves (vs. lanceolate, papyraceous leaves).
