Checklist Flora of Native and Naturalized Vascular Plants of Golden and Vicinity, Jefferson County, Colorado, 2020 Edition Tom Schweich, 420 Arapahoe Street, Golden, CO 80403 Email: [email protected] makes it easier to compare georeferencing to Golden, Colorado sits in a valley formed by described collecting location. erosion along the Golden fault, the geotectonic boundary between the North American Cordillera 2. Identify questionable collections or and the Great Plains. Somewhat like Mono Lake, determinations. Some examples might be: for which I have also prepared a checklist flora, it 1. A collection dated 1822 from Golden, sits at a boundary, or perhaps ecotone. Things are although Golden was not named until always more interesting at the boundaries. I 1859. This turned out to be an E. L. started this project when I realized no such list Greene collection from 1872. had been prepared for my newly adopted city. I 2. A collection to which two different names hope you find this checklist flora helpful. Please have been applied. For example, Ernest H. write to me if you have questions or comments. Brunquist's PM-123 is determined as Cirsium undulatum (Nutt.) Spreng at Introduction KHD, and C. ochrocentrum A. Gray at CS. The thing to do is to look at both vouchers It is probably fair to ask why one would prepare a and determine which name should be local flora. applied, or whether the collection was There are many sources of information about really a mixed collection. plant names, their descriptions, and how to 3. A little subtler case occurs when there are identify them. There are numerous published many single collections of related taxa. floras for the whole state of Colorado, Colorado For example, among Oenothera and Gaura east slope and west slope, and the Intermountain (which is sometimes placed in Oenothera), Region, not to mention the less-scholarly there are nine taxa for which there is only wildflower books. The various data bases will one collection in Golden and vicinity, and permit preparation of plant lists for a location, or the remaining four taxa collected here a range of geographic coordinates, will also giving have only two collections each. It seems link to further web sites such as Flora of North unusual that there would be so many America (FNANM) an Encyclopedia of Life. These single collections of a taxon, and perhaps are all excellent resources. I used them all myself some of them are misidentified. in the preparation of this flora. Data base lists 3. Identify gaps in collections. Why hasn't an selected by geographic coordinates, and those expected common species found in a certain selected by named localities, were used to provide area? an initial list of collections. The published floras of larger regions were used to check on names, For example, I found what I thought was descriptions, and distribution. Brickellia californica on North Table However, the editing process of reviewing Mountain. Yet my data base searches yielded collections, and reviewing the absence of no records of collections. Searching again for collections, provides the benefits that come from all collections of B. californica in Jefferson preparing a local flora: and surrounding counties showed a single collection of the taxon by Loraine Yeatts on 1. Apply local knowledge of geography to South Table Mountain. However, the collections, their name determinations, and collection had been georeferenced incorrectly georeferencing. Living in a location can give a and would not have appeared in a simple data better understanding of local geography, and base query. I have added that collection (and the location of historic reference points. This taxon name) to the local flora and sent a Golden Checklist Flora 1 Golden City Limits Golden sensu latu (s.l.) comment to the herbarium about the incorrect coordinates. Geography 4. Fill in gaps in collections, collect in under- Golden City Limits collected areas, or of under-collected plants. The boundaries of incorporated Golden are quite irregular. They stretch from I-70 on the south to For example, mapping the locations of north of Golden Gate Canyon on the north. The collections that can be georeferenced showed western boundary includes significant portions of that there are few collections from the lower the slopes of Lookout Mountain, but do not extend slopes of Lookout Mountain and no collections to a ridge line or natural boundary for the from the small northern portion of Dakota purposes of this flora. On the east side, the Coors Ridge near the Rooney Road Sports Complex. Technology Center comprises a large isolated These areas may now be targeted for incorporated area north of 44th and west of collecting. MacIntyre. This results in incorporated Golden on the east and west sides of North Table Mountain, 5. Identify plants that may have been extirpated but the mountain itself is not part of the City of or may be new arrivals. Golden. Only a small part of South Table Mountain is within the City of Golden. Pleasant An example might be my collection 1109 of Valley is unincorporated Jefferson County, but Balsamorhiza sagittata on Tin Cup Ridge. there are irregular sections, including a business Usually this plant is on the west slope only. park south of 6th and east of Indiana. How did it get here to the east slope? Within the City of Golden, there are a few parcels Generally, it is suggested that it was planted. that are city-owned, and large enough to be But, was it intentionally planted in an out of collected. The Fossil Trace Golf Course occupies the way place? Or planted by a bird? Or 216 ac. (87 ha.). It is not really a hotbed of another animal? biodiversity, but the elk like to hang out there in the winter. City-owned open space on the west 6. Understand the history of botanic or floristic and south slopes of North Table Mountain work in a local area. Who collected? Why? comprises 135 ac. (54 ha.). Eagle Ridge is the third largest parcel at 79 ac. (32 ha.) and the Generally, I follow nomenclature of the Flora of Grampsas Sport Complex contains 58 ac. (24 ha.). North America (1993+). When a plant name is There is a small hilly parcel near the top of found in a published volume of FNANM, I will use Washington Avenue of 4 ac. (1.6 ha.). This last it. parcel is perhaps the most interesting as it In the case of unpublished volumes of FNANM, I contains a relatively intact small (1.5 ac.) generally review multiple sources, starting with remnant mixed-grass prairie on the top of the hill. Ackerfield (2015), the Plant List (http://www.theplantlist.org/), USDA Plants, the Golden sensu latu (s.l.) Jepson Manual, Weber and Wittmann (2012), and In describing “Golden” in the broad sense, sensu Harrington (1954), and then pick a modern name latu, I have attempted to smooth the boundaries in common usage. As additional volumes of of the incorporated City of Golden, look for FNANM are published, some of the names may natural boundaries, and avoid development have to change. encroaching on open space, e.g., north slope of Once a name is selected, different names given in North Table Mountain. Ackerfield (2015), Weber and Wittmann (2012), or From the northwest corner of Golden on Pine Harrington (1954), are listed as synonyms. Ridge Road, the boundary curves across the undeveloped slopes of North Table Mountain to the business park at 44th and McIntyre. The eastern boundary is along McIntyre Street, jogging west to avoid the Rolling Hills Country Club and former Camp George West. There is an eastward extension to include the little piece of Golden at 6th and Indiana. 2 Golden Checklist Flora Geography Geography Zion. From Mount Zion back to Pine Ridge Road, I basically draw a straight line along the various western extents of the irregular Golden city limits. The definition of Golden s. l. includes much of the southwest corner of the Golden quadrangle and the northwest corner of the Morrison quadrangle. The Evergreen and Ralston Buttes quadrangles do not include any portion of Golden s. l. as I have defined it. North Table Mountain North and South Table Mountains separate Golden from the metropolitan Denver area to the east. They would be a single mountain except for the canyon that Clear Creek has cut between them. Both mesas are formed of Denver Formation capped by two or three basalt flows. The basalt erupted from what we now call the Ralston dike. This dike can be seen in a quarry west of Figure 1. Golden, Colorado, and Vicinity. Colorado Highway 93, about 3 miles north of The south boundary is the lower northwest slopes North Table Mountain. The Denver Formation is of Green Mountain, i.e., Green Mountain is composed of sedimentary rocks with clasts of excluded, I then follow Interstate 70, and a ridge volcanic rocks. The Cretaceous-Tertiary boundary line separating the incorporated area of Golden is thought to be in the lower part of the Denver from Mount Vernon Canyon. Both Tin Cup Ridge Formation. and Apex Open Space Park are therefore included Nearly all North Table Mountain is in public within Golden s.l. ownership. The largest part, about 1,873 acres, is The western boundary begins where the ridge line owned by Jefferson County, and managed by intersects the western edge of the Morrison Jefferson County Open Space as North Table quadrangle, and the boundary of Golden s.l. is the Mountain Park. This park is very popular and easternmost of either the quadrangle boundary or heavily used all year around.