K.  Suetsugu, Suleiman, M., and Tsukaya, H., ?A new species of Gastrodia (Gastrodieae, Epidendroideae, Orchidaceae) from the Maliau Basin Conservation Area, Sabah, Borneo?, Phytotaxa, vol. 367, pp. 78 - 84, 2018.

K.  Suetsugu, Suleiman, M., and Tsukaya, H., ?A new variety of the mycoheterotrophic orchid Didymoplexis obreniformis (Orchidaceae) from Borne, Malaysia?, Acta Phytotax. Geobot., vol. 68(2), pp. 105 - 109, 2017.

H.  Tsukaya, Nakajima, M., and Okada, H., ?Didymoplexiella cinnabarina (Orchidaceae): a new species from Muller Range, Central Kalimantan, Indonesia?, Acta Phytotax. Geobot., vol. 56(3), pp. 207 - 212, 2005.

K.  Suetsugu, Sugimoto, T., and Tsukaya, H., ?Emended description and new localities of Oxygyne shinzatoi (Burmanniaceae/Thismiaceae), with discussion of phylogenetic relationships of Oxygyne from Japan and Africa?, Phytotaxa, vol. 423(4), pp. 238 - 246, 2019.

E. A.  Shepeleva, Schelkunov, M. I., Hrones, M., Sochor, M., Dancak, M., Merckx, V. S. F. T., Kikuchi, I. A. B. S., Chantanaorrapint, S., Suetsugu, K., Tsukaya, H., Mar, S. S., Luu, H. T., Li, H. - Q., Logacheva, M. D., and Nuraliev, M. S., ?Phylogenetics of the mycoheterotrophic genus Thismia (Thismiaceae: Dioscoreales) with a focus on the Old World taxa: delineation of novel natural groups and insights into the evolution of morphological traits?, Bot. J. Linn. Soc., vol. 193, pp. 287 - 315, 2020.

A. B. I. S.  Kikuchi and Tsukaya, H., ?Epitypification with an embeded description of Tropidia connata (Orchidaceae, Epidendroideae, Tropidieae)?, PhytoKeys, vol. 80, pp. 77 - 85, 2017.

A. B. I. S.  Kikuchi, Keßler, P. J. A., Schuiteman, A., Murata, J., Ohi-Toma, T., Yukawa, T., and Tsukaya, H., ?Molecular phylogenetic study of the tribe Tropidieae (Orchidaceae, Epidendroideae) with taxonomic and evolutionary implications?, PhytoKeys, vol. 140, pp. 11 - 22, 2020.

K.  Suetsugu, Tsukaya, H., Nurainas, N., and Okada, H., ?Thismia sumatrana (Thismiaceae), a new species from West Sumatra, Indonesia, with discussions on the taxonomic identity of Thismia clavigera?, PhytoKeys, vol. 113, pp. 59 - 67, 2018.

K.  Suetsugu, Kikuchi, A. B. I. S., Suleiman, M., and Tsukaya, H., ?New distributional records for the mycoheterotrophic orchid Kalimantanorchis nagamasui from Sabah, Borneo, Malaysia?, Acta Phytotax. Geobot., vol. 68(2), pp. 117 - 121, 2017.

K.  Suetsugu, Tsukaya, H., and Ohashi, H., ?Sciaphila yakushimensis (Triuridaceae), a new mycoheterotrophic plant from Yakushima Island, Japan?, J. Jap. Bot., vol. 91, pp. 1 - 6, 2016.

K.  Suetsugu, Suleiman, M., Anthony, F., and Tsukaya, H., ?Aphyllorchis maliauensis (Orchidaceae), a new species from the Maliau Basin, Sabah, Borneo?, Phytotaxa, vol. 367(1), pp. 85 - 90, 2018.

H.  Tsukaya and Hidayat, A., ?A new species of Gastrodia (Orchidaceae: Gastrodieae, Epidendroideae) from Java?, Phytotaxa, vol. 273(1), pp. 77 - 80, 2016.

K.  Suetsugu, Tsukaya, H., Tagane, S., Chhang, P., Yukawa, T., and Yahara, T., ?Flora of Bokor National Park VII: Thismia bokorensis (Burmanniaceae), a new species representing a new generic record?, Phytotaxa, vol. 334(1), pp. 65-69, 2018.

K.  Suetsugu, Tsukaya, H., Tagane, S., Suddee, S., Rueangruea, S., and Yahara, T., ?Thismia brunneomitroides (Thismiaceae), a new mycoheterotrophic species from southern Thailand?, Phytotaxa, vol. 314(1), pp. 103 - 109, 2017.

H.  Tsukaya, Suetsugu, K., and Suleiman, M., ?Thismia bryndonii (Thismiaceae), a new species from Maliau Basin, Sabah, Borneo?, Phytotaxa, vol. 312(1), pp. 135 - 138, 2017.

H.  Tsukaya, ?Burmanniaceae?, in Flora of Japan. Vol IVb, K.  Iwatsuki, Boufford, D. E., and Ohba, H. (eds.), Eds. Tokyo: Kodansha Publisher, 2016, pp. 194 - 197.

K.  Suetsugu, Suleiman, M., and Tsukaya, H., ?A new species of Gastrodia (Gastrodieae, Epidendroideae, Orchidaceae) from the Maliau Basin Conservation Area, Sabah, Borneo?, Phytotaxa, vol. 367(1), pp. 78 - 84, 2018.

M.  Cheek, Tsukaya, H., Rudall, P. J., and Suetsugu, K., ?Taxonomic monograph of Oxygyne (Thismiaceae), rare achlorophyllous mycoheterotrophs with strongly disjunct distribution?, PeerJ, vol. 6, p. DOI 10.7717/peerj.4828, 2018.

J.  Yokoyama, Koizumi, Y., Yokota, M., and Tsukaya, H., ?Phylogenetic position of Oxygyne shinzatoi (Burmanniaceae) inferred from 18S rDNA sequences?, J. Plant Res., vol. 121, pp. 27 - 32, 2008.

H.  Tsukaya, ?How have leaves of mycoheterotrophic plants evolved - from the view point of a developmental biologist?, New Phytol., 2018.

H.  Tsukaya, Yokota, M., and Okada, H., ?Chromosomal characteristicsof 0xygyne shinzatoi (Burmanniaceae), and its phylogenetic significance?, Acta Phytotax.Geobot., vol. 58(2/3), pp. 100 - 106, 2007.

H.  Tsukaya and Okada, H., ?A new species of Lecanorchis Blume (Orchidaceae, Vanilloideae) from Kalimantan, Borneo?, Syst. Bot., vol. 38(1), pp. 69 - 74, 2013.

H.  Tsukaya and Suetsugu, K., ?Two new species of Sciaphila (Triuridaceae) from Sarawak (Borneo, Malaysia)?, Phytotaxa, vol. 170 (4), pp. 283 - 290, 2014.

H.  Tsukaya and Okada, H., ?A new variety of Didymoplexis cornuta (Orchidaceae) from West Kalimantan, Borneo?, Acta Phytotax. Geobot., vol. 62 (2/3), pp. 89 - 93, 2012.

H.  Tsukaya and Okada, H., ?A color variaton of Epirixanthes species (Polygalaceae) found in West Kalimantan, Borneo, Indonesia?, Acta Phytotax. Geobot., vol. 62 (2/3), pp. 95 - 97, 2012.

H.  Tsukaya, Suleiman, M., and Okada, H., ?Didymoplexiella trichechus (J.J.Sm.) Garay and a new variety of Didymoplexis cornuta J.J.Sm. (Orchidaceae) in Borneo?, Acta Phytotax, vol. 62 (2), pp. 105 - 110, 2014.

H.  Tsukaya, Suleiman, M., and Okada, H., ?A new species of Epirixanthes (Polygalaceae) from Imbak Canyon, Sabah, Borneo?, Phytotaxa, vol. 266 (2), pp. 146 - 150, 2016.

H.  Tsukaya, Suleiman, M., and Okada, H., ?A new variety of Thismia hexagona Dan?ák, Hrone?, Koblová et Sochor (Thismiaceae) from Sabah, Borneo, Malaysia?, Acta Phytotax. Geobot., vol. 65, no. 3, pp. 141-145, 2014.

H.  Tsukaya and Okada, H., ?Two new species of Sciaphila Blume (Triuridaceae) from Kalimantan, Borneo, with a new record of S. thaidanica from Borneo?, Syst. Bot., vol. 38, no. 3, pp. 600-605, 2013.

H.  Tsukaya and Okada, H., ?A new species of Thismia (Thismiaceae) from West Kalimantan, Borneo?, Syst. Bot., vol. 37(1), pp. 53 - 57, 2012.

H.  Tsukaya, Nakajima, M., and Okada, H., ?Kalimantanorchis: a new genus of mycotrophic Orchid from West Kalimantan, Borneo?, Sys. Bot., vol. 36(1), pp. 49 - 52, 2011.

J.  Yokoyama, Fukuda, T., and Tsukaya, H., ?Molecular identification of the mycorrhizal fungi of the epiparasitic plant Monotropastrum humile var. glaberrimum (Ericaceae)?, J. Plant Res., vol. 118, pp. 53 - 56, 2005.

H.  Tsukaya, Yokoyama, J., Imaichi, R., and Ohba, H., ?Taxonomic status of Monotropastum humile, with special reference to M. humile var. glaberrimum (Ericaceae, Monotropoideae)?, J. Plant Res., vol. 121, pp. 271 - 278, 2008.

T.  Yahara and Tsukaya, H., ?Oxygyne yamashitae, a new species of Thismiaceae from Yaku Island, Japan?, Acta Phytotax. Geobot., vol. 59(2), pp. 97 - 104, 2008.

H.  Tsukaya and Okada, H., ?Thismia mullerensis (Burmanniaceae), a new species  from Muller Range, central Kalimantan?, Acta Phytotax. Geobot., vol. 56(2), pp. 129 - 133, 2005.

H.  Tsukaya, ?Flowering time of two saprophytic plants, Monotropa uniflora L. and Monotropastrum humile (D. Don) Hara in Japan?, J. Plant Res., vol. 111, pp. 595 - 597, 1998.