Plant Guide and Key to Shrubs and Trees Of The Granite Loop Trail, Santa Rosa Plateau
Introduction and Explanation of Plant Trail Guides
Highlights of This Trail
The Plant Guide
Version for printing, without lines and other text on this page
This is a guide to all the species on this trail that are shrubs or trees that have at least one specimen that is taller than ~1 m (3 feet). Unlike my usual guides, I do not always give the location of the very first specimen on the trail. Instead, I give the location of the first obvious or good specimen on the trail that can be easily located at the point given in the guide.
Therefore all the specimens given in this guide should be visible at any time of the year, with the exception of four species with deciduous leaves: deerweed, Lotus scoparius var. scoparius; white-flowered currant, Ribes indecorum; poison oak, Toxicodendron diversilobum; and skunkbush, Rhus trilobata.
I also include a key to identify each of the species. The key does not use flowers, and so can be used any time of the year, except for the three species with deciduous leaves. Even then, you might be able to find their leaves in the leaf litter under each shrub. (Warning! Use your eyes only, since poison oak leaves can still affect you even when dried.)
Keys are notoriously difficult to use by a beginner. However, after you have keyed each one of the 23 species in the key, you will then gain an excellent understanding of how to use this key. Each of the species on this trail can usually be keyed in a single trip, allowing even a beginner to quickly learn how to use such a key, and confidently recognize these 23 species on this trail.
Testing this key with the SRP Docent Class on 18 October 2003 revealed that the tricky couplets are #1, #5 and #19. As you begin to use this key, if you find you have keyed out a plant to an incorrect id, those are the couplets to return to and see if you should have taken the other branch.
To learn how to key out and recognize the shrubs and trees on this trail, first use the Plant Guide to find the first occurrence of each species on the trail. Then use the Key to verify that you have found that species. Once you have gone through most of the branches of the key, you should then be able to key out any specimen from each of those species anywhere on the trail.
Complete guide to all plants on this trail.
Highlights of This Trail
The botanical highlights of this trail, as seen using this guide, are:
- Every shrub and tree on this trail is a native plant. Despite the presence of a large number of non-native annuals, no non-native shrub or tree has managed to invade this area.
- Note that only two species, chamise (Adenostoma fasciculatum) and California buckwheat (Eriogonum fasciculatum var. foliolosum), are found in large numbers on this trail. Only nine other species are found in more than nine locations along the trail. The other 13 species are found in three or fewer locations.
- For comparison, note that over 160 annual and perennial herbs are also found on this trail.
The Plant Guide
Mile s # Common Name Latin Name #here #all 0.00 South Trailhead. This guide notes only the shrubs and trees taller than 1 m (3 feet). A key to identify these species follows the guide. The first obvious location for each species is given here; in a few cases, a specimen will occur earlier, for those with sharp eyes. 0.00 l 1 California buckwheat Eriogonum fasciculatum var. foliolosum 99 / 9 25 0.00 l 2 chamise Adenostoma fasciculatum 99 / 9 18 0.00 l 3 southern honeysuckle Lonicera subspicata var. denudata 50 / 9 20 0.00 r Sign: "Granite Loop Trail". 0.00 l 4 saw-toothed goldenbush Hazardia squarrosa var. grindelioides 25 / 9 18 0.00 r 5 Torrey's scrub oak Quercus acutidens 20 / 9 8 0.02 l 6 deerweed (often hard to see except in spring) Lotus scoparius var. scoparius 10 / 9 15 0.02 Begin small uphill 0.04 r Boulder with hiding place under an overhang. 0.04 r 7 redberry Rhamnus crocea 10 / 9 5 0.04 End small uphill and descend 0.04 l Four tall rocks look like they are having a boring conference, with one poor fellow asleep. 0.05 Trail bends 90° to left, rounding the tall rocks on left, then 90° to right; view of Mesa de Burro 0.06 l 8 hollyleaf redberry Rhamnus ilicifolia 50 / 9 21 0.07 l 9 bush monkeyflower Mimulus aurantiacus 10 / 9 20 0.08 b 10 black sage Salvia mellifera 5 / 1 20 0.12 r Upper jct. with steeper old trail. 0.14 r Lower jct. with old trail. 0.15 r 11 poison oak Toxicodendron diversilobum 50 / 9 20 0.15 b 12 coast live oak Quercus agrifolia var. agrifolia 30 / 9 29 0.17 Leave chaparral; now paralleling drainage on left; nodding needlegrass, Nassella cernua, on right, to compare with purple needlegrass, Nassella pulchra, a bit ahead on left. 0.19 13 Engelmann oak Quercus engelmannii / 15 0.20 Beginning of bridge over drainage 0.20 l (mule fat, Baccharis salicifolia) 0.20 r 14 arroyo willow Salix lasiolepis 1 / 1 19 0.20 End bridge 0.22 l Trail curves around a large clump of giant wild rye, Leymus condensatus. 0.26 l Top of "flying saucer" rock. 0.28 r 5 foot tall boulder, immediately before the next species 0.28 r 15 white-flowering currant Ribes indecorum 3 / 3 8 0.32 Cross small bridge (a short side trail to left on other side) 0.34 b 16 skunkbush Rhus trilobata 10 / 3 8 0.34 r 17 California sagebrush Artemisia californica 1 / 1 23 0.34 r 18 toyon Heteromeles arbutifolia 2 / 2 24 0.36 r Jct. 10' side trail to "hollow-sounding rock" (exfoliating granite in ground) 0.45 Leave chaparral, enter drainage filled with mostly deergrass, Muhlenbergia rigens. Trail parallels double drainage for a short distance, with small drainage on left and main drainage on right. 0.53 l 19 Vasey's prickly pear Opuntia Xvaseyi 1 / 1 10 0.53 Cross small bridge over a very small drainage that doesn't appear to go anywhere. 0.60 r 20 western sycamore Platanus racemosa 1 / 1 11 0.60 Beginning of bridge 0.61 End bridge, with best patch of goldenrod, Solidago californica, here. 0.64 r 21 blue elderberry Sambucus mexicana 2 / 2 21 0.67 r 22 Palmer's goldenbush Ericameria palmeri var. pachylepis 5 / 1 2 0.68 Cross Waterline Road 0.70 r Jct. Vista Grande Trail 0.77 Enter chamise forest here or a bit earlier 0.78 Oak moss lichen, Evernia prunastri, is the interesting foliose (leaf-like) lichen growing on the shrubs. 0.89 r Jct. unauthorized path, closed by a serious fence in May 2002. 0.90 Begin scattered coast live oaks 0.90 Jct. shortcut road to Visitor Center on left; go right 0.94 Leave chamise forest, enter coast live oak woodland 0.98 Jct. "closed trail" to inholding; enter meadow on right 1.04 l View of woodrat's nest in tree to east. 1.04 l Picnic tables 1.06 r 23 San Diego mountain mahogany Cercocarpus minutiflorus 1 / 1 6 1.15 r Jct. old connector trail (to Multiuse Trail), fenced halfway between the trails now. 1.16 End trail
Key To Identify Shrubs And Trees On This Trail Taller Than 1 m (3 feet) 1 mature plant a tall tree (usually a single trunk from ground)............Go to 2 1' mature plant a shrub (usually multiple stems from ground)..........Go to 4 2 leaf large, outline roundish, roughly covering the size of your palm, with three main lobes cut about halfway to leaf base; lower surface soft, fuzzy; fruit in stalks with 3-5 separate spherical clusters, not an acorn..........western sycamore, Platanus racemosa 2' leaf smaller than your palm, outline not roundish; often with acorns or acorn caps present.........Go to 3 3 leaves bluish-gray-green or grayish-green, flat .... Engelmann oak, Quercus engelmannii 3' leaves green, with edges usually curled toward the lower leaf surface....... coast live oak, Quercus agrifolia var. agrifolia 4 plant without a normal stem or leaves, body consisting of roundish succulent pads with regular clusters of large spines ...............Vasey's prickly pear, Opuntia Xvaseyi 4' plant with normal stem and leaves, without large spines ........Go to 5 5 leaves always opposite (in pairs of 2, each leaf appearing opposite the other on the stems).....Go to 6 5' leaves mostly alternate on the stems (appearing singly, with no other leaf on the other side of the stem opposite to each leaf).....Go to 9 6 leaf compound (made up of distinct, cleanly-separated leaflets).............blue elderberry, Sambucus mexicana 6' leaf simple, not compound...........Go to 7 7 upper branches thin, flexible, seldom erect, sometimes vine-like............wild honeysuckle, Lonicera subspicata var. denudata 7' upper branches rigid, erect.........Go to 8 8 Remnants of flower clusters from previous year usually present, the clusters surrounding the stem with large empty spaces between clusters on each stem; lvs aromatic; leaf yellowish-green, usually wider than 5 mm (1/5"), with a network of obvious veins; stem of twigs distinctly square, not round............black sage, Salvia mellifera. 8' Remnants of flowers from previous year never present, if present, flowers single, one in each leaf axil; leaves usually sticky except in the dry season, dry season leaves 1-5 mm (1/25-1/5") wide; stem of twigs roundish...............bush monkeyflower, Mimulus aurantiacus 9 lvs compound (made up of distinct, cleanly-separated leaflets).........Go to 10 9' lvs simple, not compound............Go to 12 10 leaflets smooth-edged, leaflets shorter than 15 mm (5/8") and not much wider than 3 mm (1/8").............deerweed, Lotus scoparius var. scoparius 10' edges of lflets variously lobed or toothed; lvs deciduous...........Go to 11 11 terminal leaflet with a distinct stalk............poison oak, Toxicodendron diversilobum 11' terminal leaflet without a distinct stalk...........skunkbush, Rhus trilobata 12 lvs very narrow in width, width less than 3 mm (1/8").........Go to 13 12' lvs with width significantly larger than 3 mm (1/8").............Go to 16 13 longest lvs branched into threadlike lobes, total leaf length 1-10 cm (1/2-4") long, aromatic.............California sagebrush, Artemisia californica 13' lvs unbranched...........Go to 14 14 flowers in flat-topped clusters, white, turning rust-color and persisting for most of the year; oldest, largest leaves with leaf edges rolled under, underside of leaf white; younger leaves almost round in cross-section with no discernible top or bottom, ............California buckwheat, Eriogonum fasciculatum var. foliolosum 14' flowers not in flat-topped clusters, not persisting most of the year; leaf edges either not noticeable or never rolled under ...........Go to 15 15 youngest twigs reddish-brown; plant often much taller than 1 m (3')............chamise, Adenostoma fasciculatum 15' youngest twigs yellow-green to light green; plant never much taller than 1 m (3').................Palmer's goldenbush, Ericameria palmeri var. pachylepis 16 lf blade with palmate veins (main veins branching from base and producing a outline like your palm); leaf with palmate lobes; lvs deciduous...............white-flowered currant, Ribes indecorum 16' lvs pinnately-veined (veins like a feather, having a main central vein with side branches)..........Go to 17 17 leaf blade without threadlike lobes, more than five times longer than wide, gen longer than 7 cm (3"); lvs flexible, usually symmetric about the middle (when folded lengthwise, the two halves are nearly identical).......arroyo willow, Salix lasiolepis 17' leaf blade with threadlike lobes, OR less than four times longer than wide, gen shorter than 7 cm (3"); lvs not easily folded; if able to fold lengthwise without breaking, not symmetric about the middle.............Go to 18 18 lvs aromatic, longest lvs branched into threadlike lobes, total leaf length 1-10 cm (1/2-4") long...................California sagebrush, Artemisia californica 18' lvs not aromatic, without threadlike lobes.............Go to 19 19 many lf blades less than twice as long as wide, or if most leaves are ~twice as long as wide, plant often with acorns or acorn caps .............Go to 20 19' nearly all lf blades distinctly more than twice as long as wide...........Go to 23 20 acorns or acorn caps often present........Torrey's scrub oak, Quercus acutidens 20' acorns or acorn caps never present..............Go to 21 21 most leaves on short, spur-like branches; fruit a seed with a 5-8 mm (2-3") long silky plume, not a berry..............San Diego mountain mahogany, Cercocarpus minutiflorus 21' leaves not on short, spur-like branches; fruit a red berry.............Go to 22 22 leaf blade < 15 mm (5/8"), flat, branches making ~45° angles, often with spine-like tips...........redberry, Rhamnus crocea 22' leaf blade > 15 mm (5/8"), lower side often concave; branches not angled widely, never with spine-like tips .............. hollyleaf redberry, Rhamnus ilicifolia 23 lvs with a distinct petiole (stalk below the blade), petiole 3 mm (1/8") or longer; lvs green above, paler below, evenly and sharply toothed around the edges; fruit a berry...........toyon, Heteromeles arbutifolia 23' petiole indistinct or lacking, the blade tapered to base; plant a low-growing shrub, rarely taller than 1 m (3'), woody only at base, lvs sharply toothed all around; fr a seed with pappus (like dandelion fluff)..........saw-toothed goldenbush, Hazardia squarrosa var. grindelioides
Images linked in the key supplied by Jane Strong. I thank Jane for useful comments on the key as well.
Copyright © 2003-2004 by Tom Chester.
Permission is freely granted to reproduce any or all of this page as long as credit is given to me at this source:
Comments and feedback: Tom Chester
Updated 30 December 2004.