Monday, July 19, 2010

Jepson Herbarium Poaceae Workshop at Jasper Ridge (May 2010)
Instructor Travis Columbus

Friday, May 15, 2009

May 6, 2009. Vulpia octoflora var. hirtella. A collection was made at the sharp turn on trail 9. JH Thomas' 1958 collection of Vulpia octoflora v. octoflora, recently re-determined to Vulpia octoflora var. hirtella, was from the Escobar Gate area.

Also blooming on trail 9 were several Phacelia rattannii, Cryptantha clevelandii (several spots), C. micromeres (near the Vulpia octoflora). C. micromeres is also blooming on the Rattlesnake Rock trail. Sunday evening on Rd E approaching the big inlet from the downhill side I collected the single-nutleted Cryptantha microstachys. C. flaccida is still in bloom on serpentine. Just west of the Vulpia octoflora var. hirtella before the Sanicula laciniata site and the beginning of Buckeye alley, about 30 purported Githopsis specularioides were in bloom on the uphill side of the trail. They were photographed but no collection was made. The plants were gone when a collecting party returned to the site two weeks later. Hesperolinom micranthum was blooming in the same area (also in trail 11 in chaparral). Linanthus pygmaeus ssp. continentalis was also blooming on trail 11 at its usual spot. Several tiny plants of Heterocodon rariflorum were in fruit on trail 10 at the edge of chaparral along with Yabea microcarpa, Daucus pusillus, Linanthus bicolor, and Pectocarya pusilla.

photo above: Vulpia octoflora. Photo by Toni Corell.
photo left: Linanthus pygmaeus ssp. continentalis. Photo by Toni Corell.

Sunday, December 14, 2008

A walk in Jasper Ridge's serpentine prairie, an article appearing in Grasslands, Spring 2008. Correction: A.G. Vestal was a member of Stanford's Biology Dept., not a Carnegie Institution research scientist. Photo by Toni Corelli.

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.

Monday, November 03, 2008

Slender false brome,
Brachypodium sylvaticum.

One plant discovered on preserve near Sandhill Rd. in 2007. Extirpated. This distinctive perennial forest grass has sessile spikelets, long-awned lemmas, and densely hairy nodes. It has naturalized and is locally abundant in Huddart Park (San Mateo County) and MPROSP Thornewood Preserve and adjacent private land.

See California Invasive Plant Council plant profile

Monday, October 15, 2007

Reduction of exotic grasses in serpentine

Lolium multiflorum has become a dominant plant in portions of Jasper Ridge's serpentine prairie over the past three decades. A variety of discussions in April 2007 led to a suggested experiment in area H of the serpentine grassland (see map) to try and reduce exotic grasses. Based on the experience of Stu Weiss at Edgewood Park, and others elsewhere, there is evidence that mowing of grasses can help increase population densities of the food plants of the Bay checkerspot butterfly in the year following mowing.

Proposal: mowing at 6" height without followup raking because raking had no additional effect in Weiss' studies; mowing closer to the ground, and perhaps raking as well, would likely impact arthropods and herps. Based on Richard Hobbs' observation that late summer rain appears to trigger germination of grasses much more than forbs, and, if followed by a month of dry weather, cause a false start to the growing season, we are suggesting a watering treatment in August. The water would be applied via some type of soaker hose from a water truck (to deliver 1cm of water would take a couple of trips with the water truck).

These two treatments should be compared with controls and replicated 4 times in an area near a fire road. Each plot will be 3m x 10 or 15m, with 12 plots total, and buffers between plots.

Area H Mow Area Plant List; choose Area H work sheet. This plant list was compiled by the Herbarium crew walking through the proposed site on May 2, 2007.

Monday, August 27, 2007

Newly proposed checkerspot critical habitat

The new US Fish and Wildlife proposal for Bay checkerspot critical habitat is a modification of the critical habitat outlined in 2001 (which was sent back to F&W by a lawsuit). A final determination will be made by Aug 14, 2008.

Changes in the critical habitat were made based on decisions about the physical and biological features that are essential to the conservation of the butterfly. Some areas that are non-grassland or extensively developed
were dropped, while a Pulgas Ridge unit was added because it historically supported the Bay checkerspot and could be a stepping stone between the San Bruno Mountain unit and the southern San Mateo County units (Edgewood Park
and Jasper Ridge). In total, the current proposed area is smaller than the 2001 rule by about 4,000 acres, and includes 329 acres (133 ha) at Jasper Ridge.

The following website includes a link to the Federal Register with the revised proposal, which has a fairly detailed discussion of the revised critical habitat units.

Nona Chiariello