ILLUSTRATIONS. 11 



36. Pinesap (Hypopitys lanuginosa). Rich woods in summer, the plants tawny 

 or pinkish. In the center is a frond of the Christmas fern {Polyslichum 

 acrostichoides); against the middle of the log is a frond of maidenhair 

 (Adianlum pedatum); the other ferns are beech ferns (Dryopteris 

 hexagonoptera) . 



37A, Ghost-pipes ( Thalesia uniflora) . Moist woods in May. A root parasite, the 

 flowers yellowish or bluish. 



37B. Trailing arbutus {Epigaea repens). Sterile woods in March and April. 

 Flowers pinkish. 



38. Thicket of laurel (Kalmia latifolia), along Cabin John Run in April. 



Leaves evergreen. 



39. Laurel (Kalmia latifolia). Flowers white or pink. At first the anthers 



are held in little cavities at the side of the corolla; later the elastic 

 filament straightens, suddenly releasing the anthers and throwing the 

 pollen upon a visiting bee. 



40. Deerberry (Polycodium stamineum) . A characteristic shrub in sterile 



woods; flowers white. 

 . 41A. Bluets {Houstonia coerulea). Open sterile woods in April and May. 

 Flowers pale blue or nearly white, with a yellowish center. 

 41B. Robin's plantain (Erigeron pulchellus). Common in meadows and open 



woods in April and May. Ray flowers bluish. 

 42. Japanese honeysuckle (Lonicera japonica), climbing on a dead tree. An 

 introduced vine now abundant along fence rows and edges of woods, and 

 on banks. Flowers white, fading to cream, sometimes pink. 



TEXT FIGURE. 



Page. 



Figure 1. The inflorescence, spikelet, and floret of a grass (Bromus secalinus) . . 66 



