| Therorhodion Small | |
| Publ. & Syn. | Small, N. Amer. Fl. 29: 45 (1914). |
| Notes | Elven and Murray: Kron and Judd (1990) presented good molecular evidence for accepting Therorhodion apart from Rhododendron. This is further strengthened by the analyses of Kron et al. (1999) and Kurashige et al. (2001). The northern, amphi-Beringian Therorhodion glandulosum and the more southern, amphi-Pacific T. camtschaticum (Pall.) Small (Rhododendron camtschaticum Pall.) must be closely related but are consistently different in some characters. No intermediates have been seen in the material (ALA) from Alaska where they nearly meet. We therefore accept two species. Therorhodium camtschaticum is not yet documented to reach the Arctic even if Hultén (1973) reported it from March Mountain north of Dillingham in southwestern Alaska. The three reports of diploid chromosome numbers (2n = 24, 26) included for the collective species by Löve and Löve (1975a) belong to T. camtschaticum. |
| Chromosomes | (1) 26 (2x). - Far East (N), Alaska. - Zhukova (1980); Johnson and Packer (1968). (2) 52 (4x). - Far East (N), Canada, Greenland. - At least five reports. The Johnson and Packer (1968) diploid chromosome count from northwestern Alaska (for Ledum palustre s. lat.) was entered by Löve and Löve (1975a) as L. groenlandicum, probably because it did not fit with the other counts of L. palustre. Alaskan plants of the two species are not easily confused and Rhododendron groenlandicum is not known as far west as the area in question (Ogotoruk Creek, see Hultén 1968a). A voucher should be checked before acceptance. However, the report is made more probable by a report of a diploid from South Chukotka (Zhukova 1980). |
| Geography | Asian (N/C) - amphi-Beringian - North American (N): RUS? SIB RFE ALA CAN GRL. |
| Parent taxon | Ericaceae |
| Child taxa |
Therorhodion glandulosum Standl. ex Small |
| PAF ID | 7402 |