Philipp Franz von Siebold explored Japan from 1823 to 1829 and studied the plants collected by himself and others, with Joseph Gerhard Zuccarini. They used Flora Japonica by Carl Peter Thunberg published in 1784, as the most reliable prior work of the flora. They, especially Siebold, named their collections according to Thunberg’s treatment, and noticed most of the species, which Thunberg considered to be identical with European or American ones, to be specifically different from them. In such cases Siebold gave a new name and cited the original name used by Thunberg. For the example, Siebold gave a new name, Lithospermum murasaki, for the plant which Thunberg treated as L. arvense L. His segregation is acceptable, although he did not write ‘excluded the type.’ According to the present International Code of Nomenclature for Algae, Fungi, and Plants (Melbourne Code), it is not clear whether Lithospermum murasaki is regarded as a superfluous name for L. arvense L. and therefore as illegitimate name, or not. In this article the authors discuss some of Siebold’s and Siebold & Zuccarini’s names for which original names appeared in Thunberg’s Flora Japonica.

This is part 9 of the list of type specimens and original materials of taxa described by Siebold and Zuccarini from Japan. It concerns the taxa belonging to the families ranging from Diapensiaceae to Symplocaceae according to the 12th Engler system by Melchior (1964). Four genera described as new by them, Schizocodon Siebold & Zucc., Meisteria Siebold & Zucc., Tripetaleia Siebold & Zucc., and Pterostyrax Siebold & Zucc. are included.

Lopholejeunea soae R. L. Zhu & Gradst., a species so far known only from China and Thailand, is recorded for the first time in the Indian bryoflora from West Siang district of Arunachal Pradesh in Eastern Himalaya. The species, characterized by having the leaf lobule apex attached to the leaf lobe across 2(–3) cells, belongs to section Lopholejeunea of subgenus Lopholejeunea.

For the revised edition of the “Wild Flowers of Japan” (Heibonsha Ltd., Publishers), several new names are needed for the account of Cerasus (Rosaceae). Five new combinations, C. ×chichibuensis (H. Kubota & Moriya) T. Katsuki & H. Ikeda, C. ×kubotana (Kawas.) T. Katsuki & H. Ikeda, C. ×subhirtella (Miq.) Masam. & Suzuki f. hisauchiana (Koidz. ex Hisauti) T. Katsuki & H. Ikeda; f. tama-clivorum (Oohara, Seriz. & Wakab.) T. Katsuki & H. Ikeda; and f. koshiensis (Koidz.) T. Katsuki & H. Ikeda, are proposed. Prunus takasawana H. Kubota & Funatsu, an invalid name, is proposed as nothovar. takasawana T. Katsuki & H. Ikeda under C. ×oneyamensis (Hayashi) H. Ohba. Lectotype of Prunus koshiensis Koidz. is designated.

Sida linifolia Juss. ex Cav. (Malvaceae) is reported here as a new record for Thailand. This species is described and photographed. An artificial key to the species of Thai Sida is provided.

Nyctocalos brunfelsiiflorum Teijsm. & Binn. (Bignoniaceae) from Cuc Phuong National Park, Ninh Binh Province and Thach Thanh District, Thanh Hoa Province, Northern Vietnam, is newly recorded for the flora of Vietnam. This species is characterized by leaves pinnately 3–5-foliolate; corolla tube 3–6 cm long; stamens 5, equal or subequal, not exserted. An updated description with color photographs of this species is provided.

Tsuga japonica Shiras. is lectotypified by Plate III in the protologue published in Bot. Mag. (Tokyo) 9(no. 96) in 1895.

Makino (1925) described Fimbristylis diphylloides Makino (Cyperaceae) with a short Japanese description, without any citation of specimens and localities. Tuyama (1935) gave a detailed description of F. diphylloides in Latin, citing several specimens, but he did not designate any types. A specimen, Makino might have considered as a new species by his own handwriting, was discovered in TI. The specimen is designated as the lectotype of F. diphylloides Makino.

Doodia scaberula Parris was transferred to Blechnum as B. papuanum by Christenhusz in 2011, due the pre-existence of B. scaberulum Sodiro, a South American species. However, this is a later homonym of B. papuanum Brause and thus, is here replaced by B. polinesicum. A brief description of this species is provided.

Dischidia bengalensis Colebr. (Apocynaceae), collected from Central Nepal, is reported as a new record for the Flora of Nepal. A brief description, photographs and discussion are provided.

Ludwigia longifolia (DC.) H. Hara, an annual or perennial onagraceous herb native to Brazil and northern Argentina is reported first as naturalized in Tateyama, Chiba Pref., Japan. The plant is established in the habitat since 2013, and may naturalize widely in wet habitats of Japan in future. It has already naturalized widely in the East Coast of Australia from the 1990’s.

Zeuxine membranacea Lindl. (Orchidaceae) is reported as a new record for the orchid flora of Nepal. A brief note with habitat, diagnostic key and distribution is provided.

Junior homonyms of fossil species, Abies protofirma Tanai 1961 (non Zaklinskaja 1957) and Abies minor Ananova 1974 (non Velenovský 1885), are replaced with new names res pectively, A. praefirma Doweld and Abiespollenites ananovae Doweld. The validity of the fossil species A. minor Velenovský 1885 is no more affected by the devalidated species name A. minor Gilibert 1792, which is in the works now suppressed by The International Code of Nomenclature for Algae, Fungi, and Plants (Opera utique oppressa).