~ John Mills Parrish
| Latin Name | Common Name | State Rank/Status | Occurrence | Where Found | |
|---|---|---|---|---|---|
| Category 1 - Montgomery records | |||||
| 1 | Populus heterophylla | Swamp Cottonwood | 4 mi. w.of Seneca, "marsh on Potomac R. floodplain" Uhler & Hotchkiss 1966 (SI); "above Great Falls" Bartlett (H&S) | ||
| 2 | Myrica pensylvanica | Northern Bayberry | "Woodside" Miller 1899; "Silver Spring vicinity" Pollard 1895 (Smithsonian Institution records) | ||
| 3 | Sibbaldiopsis tridentata | Three-toothed Cinquefoil | "Violet Locks Area, rock ledge, 17 April 1976" (R.E. Riefner & S.R. Hill in Castanea June 1983 citing Porter's voucher) | ||
| 4 | Amelanchier nantucketensis | Nantucket Shadbush | S1 | Potomac R. Gorge, extant (MD Natural Heritage Program) Nantucket Shadbush is often confused with A. stolonifera | |
| 5 | Baccharis halimifolia | High-tide Bush | "Cabin John vicinity" Chickering 1878 (Smithsonian Institution records) | ||
| Category 2 - Potential additions | |||||
| 1 | Itea virginica | Sweet Spires | Powdermill Bogs - Prince George's County (W.L. McAtee - Bulletin of the Biological Society of Washington, 1918) | ||
| 2 | Spirea betulifolia | Corymbed Spirea | S3 | "Sugarloaf" Frederick County Roller 1946 (SI); personal observation on top of Sugarloaf Mountain, (John Parrish 1995) | |
| 3 | Hypericum densiflorum | Glade St. John's-wort | Powdermill Bogs, Prince George's County McAtee 1917 (Smithsonian Institution records) | ||
| 4 | Rhododendron arborescens | Smooth Azalea | S3 | Difficult Run at Great Falls Park - Fairfax County, VA (extant) | |
| 5 | Gaylussacia dumosa | Dwarf Huckleberry | "Takoma" Steele 1897; Powdermill Bogs - Oldys 1903 & McAtee 1910 (Smithsonian Institution records) | ||
| 6 | Kalmia angustifolia | Sheep Laurel | S3 | Powdermill Bogs, Prince George's County. (McAtee 1918, Bulletin of the Biological Society of Washington) | |
| Category 3 - Potential add. C&O | |||||
| 1 | Smilax walterii | Coral Greenbrier | C&O Canal NHP - (Selected Vascular Plant List for C&O Canal NHP) likely found in Montgomery or DC section of park | ||
| 2 | Celtis laevigata | Sugarberry | SU | C&O Canal NHP - (Selected Vascular Plant List for C&O Canal NHP) likely found in Montgomery or DC section of park | |