Quercus × morehus explained

Quercus × morehus,^[1] Abram's oak in Kellogg's original description^[2] (later called oracle oak by Jepson^[3]), is a named hybrid between the red oaks Quercus kelloggii (California black oak) and Quercus wislizeni (interior live oak).^[4] Originally published as the unique species Quercus morehus by Kellogg,^[2] rather than as the hybrid it is called today,^[4] this tree is found in the US states of California and possibly southern Oregon,^[5] usually where the territories of the purported parents overlap.^[1]

Because the name Q. × morehus was adopted prior to 1980 while Q. wislizeni and Quercus parvula were still considered conspecific^[6] it is often applied not only to trees appearing intermediate in form between Q. kelloggii and Q. wislizeni but also those that could be Q. kelloggii × Q. parvula. Pending formal description the name Q. × ‘wootteni’ (Wootten's oak) has been proposed for the California black oak (Q. kelloggii) × Shreve oak (Q. parvula var. shrevei) hybrid.^[7]

Quercus × morehus is a hybrid between a deciduous oak and an evergreen oak. Leaves are generally deciduous or partially deciduous and intermediate in form between Q. kelloggii and Q. wislizeni.^[1]

Notes and References

1. Carl B. Wolf, “California Plant Notes I, x Quercus morehus,” Occasional Papers, Rancho Santa Ana Botanic Garden of the Native Plants of California, Volume 1 (Number 1): pages 47-52 (1938)
2. Albert Kellogg, "On a new species of Oak, brought from Clear Lake by Mr. A. A. Veatch," Proceedings of the California Academy of Sciences, series 1, volume 2: page 36 (1863)
3. Willis Linn Jepson, A Manual of the Flowering Plants of California, p. 277 (genus Quercus and some other parts 1923, the rest 1925)
4. Online link to The Jepson Manual eFlora = http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=40652 accessed 1 October 2015
5. Online link to Consortium of Pacific Northwest Herbaria (specimens #1, #4-17, #19-30, #32-34) = http://www.pnwherbaria.org/data/results.php?DisplayAs=WebPage&ExcludeCultivated=Y&GroupBy=ungrouped&SortBy=Year&SortOrder=DESC&SearchAllHerbaria=Y&QueryCount=1&Family1=fagaceae&IncludeSynonyms1=Y&Genus1=quercus&Species1=morehus&Zoom=4&Lat=55&Lng=-135&PolygonCount=0 accessed 1 October 2015
6. Kevin C. Nixon and Cornelius H. Muller, “New Names in California Oaks,” Novon, volume 4: pages 391-393 (1994)
7. Duncan A. Hauser, Al Keuter, John D. McVay, Andrew L. Hipp, and Paul S. Manos, The evolution and diversification of the red oaks of the California Floristic Province (Quercus section Lobatae, series Agrifoliae), American Journal of Botany, October 2017 104:1581-1595