2 2 FIELD AND FOREST. 



root iSanguinaria) and Saxifrage, and continuing with the delicately 

 cut-leaved Dutchman's Breeches (Duentra), the Giant Chickweed, the 

 pale, drooping Dog-toothed Violet (Erythronium), and the golden 

 Corydalis. The wealth of floral treasures reaches its maximum at High 

 Island, which is a small rocky hill lying between the canal feeder and 

 the river, just below the dam at Little Falls. Totally unfit for culti- 

 vation, it is the refuge of several species that, possibly, once had a 

 wider range, or have been brought thither by river freshets. Here we 

 find abundantly the little Erigetiia, or harbinger of Spring, the Jeffer*- 

 sonia with its curious twin leaf. Erythronium albidum grows here, and 

 the rare Solea or green Violet. A little way down the river is Chain 

 Bridge, so high it seems incredible that the river freshets have carried 

 it away twice and left no vestige of a chain about the present structure. 

 Below lies a low, rocky meadow, overflowed with evejry rise of water, 

 where we collect Ceanothtis ovalis, the small New Jersey tea, and another 

 plant that when first observed was thought to be one of the most glo- 

 rious "finds " we ever secured. It is the Baptisia aiistralis or South- 

 ern Indigo, a legimiinous plant with spikes, often a foot long, of bright 

 purplish-blue flowers, followed by large inflated pods. Elsewhere this 

 is cultivated, but here very few know of its existence. Specimens dry 

 a jet black, a perverse habit that can only be cured by a vigorous use 

 of a hot flat-iron. Alas! for the poor botanist who steals that which 

 makes him rich and none poor, both High Island and Cow-meadow 

 are now turned into sheep-pastures, and the utilitarian beasts are exter- 

 minating these interesting plants. 



The flora and fauna of a district may be limited by sharply defined 

 conditions, that only permit the growth of species which can comply 

 with them, or it may be a kind of middle ground over whose bounda- 

 ries come and mingle strangers from neighboring territory. In this 

 latter case a greater variety of kinds will of course be found, and the 

 Potomac valley is an illustration of this law. All attempts at the geo- 

 graphical distribution of plants make Virginia divide our Northern and 

 our Southern floras, and if any mere line could be selected for the pur- 

 pose, it would be the Potomac river. The Passion-flower, the Pawpaw, 

 and the Trumpet Creeper steal over it to Pennsylvania, but the Yellow 

 Jessamine {Gelsemium), the Symplocos and the Live Oak stop a little 

 short of it in the'Dismal Swamp. A few peculiar plants are usually 

 found in such districts, and we have near Washington and Alexandria 



