Thursday, November 06, 2008

Quercus cf. berberridifolia Liebm. (syn in part Quercus dumosa Nutt.)
There is an entity occasional on the Ridge, always a low shrub to 3 ft. tall, sometimes in groups of a few individuals, sometime single, usually on northern slopes 500-600 feet elevation. We have never observed acorns. The leaves are adaxially ± flat to wavy, ± shiny, green, abaxially pale green, margin mucro- or spine-toothed. We have occasioanlly noticed the adaxial leaf feature emphasized in Jepson II: "with minute appressed stellate hairs." Collections of several individuals have been made, and some plants in the field are marked with green tape.

Treatment in Jepson 2 by the late John Tucker
Q. berberidifolia Liebm.
Shrub 1-3 m or ± tree > 3 m, evergreen. LF: 1.5-3 cm; petiole 2-4 mm; blade oblong, elliptic, or ± round, adaxially ± flat to wavy, ± shiny, green, abaxially with minute appressed stellate hairs, dull, pale green, tip gen rounded, margin mucro- or spine-toothed. FR: cup 12-20 mm wide, 5-10 mm deep, hemispheric to bowl-shaped, thick, scales tubercled; nut 10-30 mm, gen ovoid, tip obtuse to acute, shell glabrous inside; mature yr 1. Dry slopes, chaparral; 100-1800 m. KR, NCoR, CaRH, SNF, Teh, ScV (Sutter Buttes), CW, SW; Baja CA. Hybrids with Quercus durata, Quercus engelmannii, Quercus garryana (Quercus howellii J.M. Tucker), Quercus john-tuckeri, Quercus lobata.
Local references to Q dumosa
  • Q. dumosa was reported by Cooper (1922, p.26) as a constituent of the climax chaparral association on Jasper Ridge. His research area was just south of the current southern boundary of the Preserve. Other oaks in this association were gold cup, leather (Q. durata), interior live. He notes that all are evergreen, except the Q. dumosa is barely so. He also lists Castanopsis chrysophylla (Chrysolepis chrysophylla) as important. Where has it gone?
  • The Preserve?s first plant list (Springer, 1935) doesn't list Q. dumosa. It does include Quercus sp., found in the chaparral.
  • Duncan Porter (1962) lists Q. dumosa and indicates that is was vouchered in the Dudley Herbaium (voucher # 100665). This voucher was later redetermined as Q. durata.
  • Dengler (1973-74) does not list Q. dumosa though he lists a number of hybrids [Q kellog x Q. wiz (morehus); Q. agrifolia x Q. wizlizenii; Q. agrifolia x Q. kellog; Q. doug x Q. lobata; Q doug x Q. durata]. The latter was confirmed by John Tucker.
  • There are transcribed lecture notes of Mooney, HA. 1978-1979 "Jasper Ridge Plant Communities [Lecture Notes]", which make reference to seven oaks at JR and a specific example in the field of Q. dumosa.
  1. Cooper, William. 1922. The broad-sclerophyll vegetation of California: an ecological study of chaparral and its related communities . Washington, D.C.: Carnegie Institution of Washington.
  2. Porter, Duncan 1962. The vascular plants of the Jasper Ridge Biological Experimental Area of Stanford. Dept. Biol. Sciences. Research Report no. 2.