590 



As has been stated already, the flora of the meadow is highly di- 

 versified. A very large number of definite interrelationships, similar 

 to those detailed for the reed swamp and the swamp meadow, are 

 found to exist, but lack of space precludes more than a brief descrip- 

 tion of a few examples. In the moist parts of the meadow, the soil 

 at a depth of 3-12 cm. frequently contains the tuberous thickened 

 roots of Cicuta maciilata and Oxypolis rigidior, and also the tuber- 

 bearing rhizomes of Equisctnui arvense. In drier situations the 

 bulbs of Liliinii canadensc occur at a similar depth (most often about 

 10 cm. deep). Higher in the soil may be found (PI. XCI, Fig. 12) 

 roots of such species as Asclepias incarnata, ThaUctmni revolutitm, 

 and Lathyrus palustris, while the surface soil contains a mixture of 

 the root systems of Poa pratensis, Agrostls alba, Bleocharis palustris, 

 Acah'pha virginica, etc. In the community shown in the figure just 

 mentioned, Eqidsetnin is edaphically complementary, but (considering 

 only the aerial sterile shoots) aerially competitive with Poa, Agrostis, 

 Bleocharis, and Acalypha. To a moderate extent, the plants rooting 

 near or at the surface appear to be complementary with the plants 

 rooting deeper. 



Small, apparently open, depressions are numerous in the moist 

 parts O'i the meadow. These generally contain (PI. XCII, Fig. 13) 

 such plants as Iris, Acorns, Viola conspersa, V. ciicullata, V. papili- 

 onacca, Cardaniine hulbosa, and seedlings of Lycopus americanus. 

 And while the rhizomes of Cardauiine and Lycopus occur almost in- 

 variably just below those of the other species, and while the different 

 species doubtless make different demands upon the soil, yet edaphic 

 competition is undoubtedly sharp. Their rhizomes are mostly short 

 and thick, lie just below or at the soil surface, and form a dense mat. 

 Nevertheless, when one or more square feet of this mat were care- 

 fully removed and the soil in the interstices among the rhizomes was 

 taken away, it was estimated that the interstices, as viewed from 

 above, constituted from 35 to 60 per cent, of the total. Evidently, 

 then, so far as mere room was concerned, several other species could 

 have grown — in fact, did grow — in these interstices. But they were 

 plants which rooted higher or lower; or, if at the same level, they 

 were species not largely dependent upon rhizomes or stolons for mul- 

 tiplication. Thus, where Iris versicolor had reached a maximum of 

 frequency, Polygonum Muhlenbergii, with a low root system, and 

 Galium Claytoni, with a high root system, might live ; but Acorus 

 Calamus, with rhizomes similar to those of Iris versicolor and lying 

 at a similar depth, and dependent largely on rhizomes for multipli- 

 cation, was absent. 



