

ILLUSTRATIONS. 



PLATES. 



Plate 1. Paint Branch, at bridge on main road east of Lewiston. (Frontis.) 



2. Drive near Piney Branch, Rock Creek Park. Tulip trees at right. 



3. Northwest Branch, northeast of Blair School. 



4. Difficult Run, looking out upon the Potomac. 



5. A rocky gorge in Difficult Run. 



6. The Potomac below Great Falls. Looking up the river from the mouth 



of Difficult Run. 



7. An old channel of the Potomac below Great Falls, looking downstream, 



the main Potomac in the distance. 

 8A. The Chesapeake and Ohio Canal below Broadwater, looking upstream. 

 A walk along the towpath of this canal, from Cabin John to Great Falls, 

 affords a fine opportunity for viewing the scenery of the upper Potomac 

 and for collecting botanical specimens. 

 8B. The Great Falls of the Potomac from the Virginia side. 

 9. Woods along the flood plain of Cabin John Run in April. The home of 

 such spring flowers as spring beauty, trout lily, and pepper-root. 



10. Marsh near Dyke. Mostly Scirpus and other sedges in the foreground. 



11. Cinnamon fern (Osmunda cinnamomea), common in marshes. Spring 



stage, as the fronds are unrolling. 



12. Christmas fern (Polystichum acrostichoides) . Woods on hilltop near Difficult 



Run, a tulip tree in middle distance. 



13. Wild rice (Zizania palustris). An extensive marsh in the upper part of 



the lower Eastern Branch. 



14. Skunk cabbage (Spathyemafoetida), along Cabin John Run in April. The 



lurid ill-smelling flowers appear before the leaves in February, being 



the earliest of our distinctively spring flowers. 

 15A . Spiderwor t ( Tradescantia virginiana) . Common along the upper Potomac 



in May; the purplish blue petals open in the morning but wither by 



midday. 

 15B. Crested iris (Iris cristata). Low rocky woods along the Potomac above 



Washington. 

 16. Marsh near Dyke. Pickerel-weed (Pontederia cordata) in foreground, the 



flowers blue. 

 17A. Spring beauty (Claytonia virginica) . Common in moist woods in early 



spring. Flowers whitish with pink veins. 

 17B. Trout lily (Erythronium americanum) . Common in moist woods in early 



spring. Flowers yellow. 

 18A. Blue phlox (Phlox divaricata). Moist woods along the Potomac in May. 

 18B . Wake-robin ( Trillium sessile) . Common in rich woodland along the upper 



Potomac, the flowers dark purple or sometimes green. 

 19A. Bellwort (Uvularia sessilifolia) . Common in woodlands below the fall 



line in April and May, the flowers greenish yellow. 

 19B. Blue flag (Iris versicolor). Bogs and marshes, in May. 



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