Ryding, O. 1980. Notes on the Aeollanthus (Labiatae) from West Africa. – Bot. Not. 133(2): 229–233.

Ryding, O. 1981. The Aeollanthus buchnerianus group (Labiatae). – Nordic J. Bot. 1: 154–164.

Ryding, O. 1982. The Aeollanthus abyssinicus group (Labiatae). – Nordic J. Bot. 2: 219–229.

Ryding, O. 1986. The genus Aeollanthus s.lat (Labiatae). – Symb. Bot. Upsal. 26.1: 1–152.

Ryding, O. 1991. Notes on the genus Erythrochlamys (Labiatae). – Nordic J. Bot. 10: 633–635.

Ryding, O. 1991. A study of the variation in Trifolium burchellianum spp. johnstonii (Fabaceae). – Nordic J. Bot. 11: 317–321.

Ryding, O. & Sileshi Nemomissa 1991. Floristic survey of three areas along the escarpment road from Asmera to Mitsiwa. – Ethiop. J. Sci. 14 (1): 41–54.

Ryding. O. 1992. Pericarp structure and phylogeny within Lamiaceae subfam. Nepetoideae tribe Ocimeae. – Nordic J. Bot. 12 (3): 273–298.

Ryding, O. 1992. The distribution and evolution of myxocarpy in Lamiaceae. – In: R. Harley (ed.), Advances in Labiate Science. Royal Botanic Gardens, Kew. pp. 85–96.

Ryding O. & Bremer, K. 1992. Phylogeny, distribution, and classification of the Coreopsideae (Asteraceae). – Syst. Bot. 17 (4): 648–658.

Ryding, O. 1993. A reconsideration of the genus Rabdosiella (Labiatae, Nepetoideae, Ocimeae). – Pl. Syst. Evol. 185 (1–2): 91–97.

Ryding, O. 1993. A new combination in the genus Endostemon (Labiatae). – Kew Bull. 48 (1): 99–104.

Ryding, O. 1993. Pericarp structure and systematic positions of five genera of Lamiaceae subg. Nepetoideae tribe Ocimeae. – Nordic J. Bot. 13 (6): 631–635.

Ryding, O. 1993. Pericarp structure of Leucas and related genera (Lamiaceae subfam. Lamioideae) – Nordic J. Bot. 13 (6): 637–646.

Ryding, O. 1994. Pericarp structure and phylogeny of Lamiaceae subfamily Pogostemonoideae. – Nordic J. Bot. 14 (1): 59–63.

Ryding, O. 1994. The pericarp structure in subtribe Melittidinae (Lamiaceae-Lamioideae) and its systematic implications. – Bot. Jahrb. Syst. 115 (4): 547–555.

Ryding, O. 1994. Notes on the Sweet Basil and its wild relatives. – Econ. Bot. 48 (1): 65–67.

Ryding, O. 1994. A new species of Plantago from Ethiopia (Plantaginaceae). – Nordic J. Bot. 14 (2): 205–207.

Ryding, O. 1994. Pericarp structure of the tribe Prasieae (Lamiaceae-Lamioideae) and its systematic implications. – Bot. Jahrb. Syst. 116 (3): 391–399.

Karis, P. O. & Ryding, O. 1994. Chapter 21 (Tribe Helenieae) and Chapter 22 (Tribe Heliantheae). – In: K. Bremer, Astreaceae – Cladistics and Classification. Timber Press, Portland, Oregon, pp. 521–624.

Ryding, O. 1994. The importance of pericarp structure in the classification of the labiates. – Lamiales Newsletter 3: 1–3.

Ryding, O. 1995. Pericarp structure and phylogeny of the Lamiaceae-Verbenaceae-complex. – Pl. Syst. Evol. 198: 101–141.

Ryding, O. 1996. Pericarp structure and phylogenetic position of the genus Wenchengia (Lamiaceae) – Bot. Jahrb. Syst. 118: 153–158.

Ryding, O. 1997. A new species of Plectranthus (Lamiaceae) from Zaire. – Bull. Jard. Bot. Nat. Belg. 66: 101–105.

Ryding, O. 1998. Teucrium (Lamiaceae) in NE tropical Africa. – Edinb. J. Bot. 55: 209–220.

Ryding, O. 1998. Phylogeny of the Leucas group (Lamiaceae). – Syst. Bot. 23: 235–247.

Paton, A. & Ryding O. 1998. Hanceola, Siphocranion and Isodon and their position in the Ocimeae (Labiatae). – Kew. Bull. 53 (3): 723–731.

Ryding, O. 1999. Pycnostachys recurvata (Lamiaceae), a new species from Ethiopia. – Novon 9: 101–103.

Ryding, O. 1999. Notes on Plectranthus (Lamiaceae) in Somalia. – Kew Bull 54: 117–127.

Ryding, O. 1999. Plectranthus alpinus (Vatke) Ryding, new combination and correct name for P. assurgens (Baker) J.K. Morton (Lamiaceae). – Bot. Jahrb. Syst. 121: 145–148.

Ryding, O. 1999. The identity of Bovonia diphylla (Lamiaceae) – Syst. Geogr. Pl. 69: 195–197.

Ryding, O. 2000. Atemporal taxa and compatibility. Taxon 49:95-96.

Ryding, O. 2000. A new species of Plectranthus (Lamiaceae) from Ethiopia and Kenya. – Nordic J. Bot. 20 (in press).

Ryding, O. 2000. The identity of some Plectranthus (Lamiaceae) from Ethiopia and Somalia. – Bot. Jahrb. Syst. 122 (in press).