Plant Species of the Bright Angel Trail: Utah juniper, Juniperus osteosperma
See Plant Guide to Bright Angel Trail for an introduction to this page, especially the Introduction To These Species Pages.
Identification status: high confidence; this is a pretty distinctive species.
There are four species of juniper in the Grand Canyon flora. Here is McDougall's key to separate them, augmented with information from the key in Kearney and Peebles, and elevation ranges given in Phillips et al 1987 and the location for J. communis:1a. Leaves awl-shaped, in whorls of 3, the upper surfaces conspicuously white; shrub usually shorter than 3 feet tall; found only on North Rim ...dwarf juniper, J. communis var. saxatilis 1b. Leaves mostly scale-like, opposite and overlapping like shingles, their upper surfaces not exposed to view; shrubs or trees usually at least 6 feet tall. (2) 2a. Small branches flattened and often drooping; berries less than 1/4 inch in diameter, usually 2-seeded; 3200-8500 feet ...Rocky Mountain juniper, J. scopulorum 2b. Small branches not flattened, not drooping; berries usually 1-seeded (3) 3a. Main trunk usually lacking, limbs arising at or below the ground level; berries 1/4 inch in diameter or less (4-7 mm); 1200 - 5500 feet elevation ...one seed juniper, J. monosperma 3b. Main trunk usually present, limbs arising above the ground level; berries 1/4 to 1/2 inch in diameter (7-18 mm); 1200 - 7800 feet elevation ...Utah juniper, J. osteosperma.
As can be seen from the pictures below, the leaves are mostly scale-like (1b), the small branches are not flattened and not drooping (2b), and there is a clear main trunk with the limbs arising well above the ground level (3b). Farther along the trail there were specimens with berries around 1/2 inch in diameter.
Note that key element 1b says mostly for the leaf characteristics. In the bottom picture, some of the older leaves are no longer appressed to the stem, and it would be possible to see their upper surfaces if you bent back the branches a bit.
Deducing that the leaves are opposite might not be obvious at first glance since the leaves are four-ranked. This means that each opposite pair of leaves is rotated 90° from the pair just below it, resulting in four columns (vertical ranks) of leaves along the twigs.
From a SEINet search, there are 21 vouchers of this species from the Coconino County portion of the Grand Canyon. The nearest are at: Grand Canyon Village at 6800 feet; and Yavapai Point at 7050 feet. Note that there may be additional vouchers at other herbaria not available through SEINet.
First occurrence on Bright Angel Trail: mile 0.00, elevation 6845 feet (2086 m).
Number of plants along Trail: at least 20 plants were found in at least 9 different locations in September 2007.
From 5 September 2007, mile 0.00:
Note the single trunk in the following picture, and the branches coming out of the trunk well above the ground level:
See Resources for Grand Canyon Flora for further information on most of these references. Entries in the second column are either the name used in that source or a page reference. The name is linked to online pages when available. If a given reference does not contain this taxon, the entry is either left blank or contains a hyphen.
Family Cupressaceae Scientific Name Juniperus osteosperma 1987 Grand Canyon Flora Name Juniperus osteosperma 1987 Grand Canyon Flora page 12 SEINet Image Page Juniperus osteosperma USDA Plants Juniperus osteosperma Flora of North America Juniperus osteosperma Jepson Manual for California treatment Juniperus osteosperma Jepson Manual illustration page 119 Kearney and Peebles Name Juniperus osteosperma Kearney and Peebles Page # 60 Vascular Plants of AZ name Juniperus osteosperma Vascular Plants of AZ volume: page 27:197 Huisinga et al 2006 name Juniperus osteosperma Huisinga et al 2006 page numbers 62 Epple Name Juniperus osteosperma Epple description page # 17 Epple pix # 33 A-B McDougall 1964 name Juniperus osteosperma McDougall 1964 page # 32 Brian 2000 Name Phillips 1979 name - Phillips 1979 page # - Stockert 1967 name - Stockert 1967 page # -
Copyright © 2007 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
Last Update: 24 September 2007