STRUCTUKE OF THE FORMATION 61 



permanent sod, which resists largely the encroachment of 

 other species. The loAver purple spikes contrast with the 

 tipper yellow staminate ones and form a conspicuous element 

 of the aspect The copious pollen of the much exserted sta- 

 mens is either transferred by means of the wind (xenogamy), 

 or showered down upon the receptive stigmas, which are 

 proterogynous and macrobiostigmatous, in such masses as to 

 color them j^ellow. In the latter case geitonogamy results. 

 Eleooharis palustris is a hydrophytic rootstalk plant, by 

 means of which it occupies a considerable area of the wet 

 meadow formation, over which it forms a dense carpet-like 

 covering. This plant is inconspicuous in every respect and 

 soon hidden from view by the taller sedges. Garex vulpifwidea 

 does not form definite patches, but is dispersed through the 

 wet meadow formation. It is at least two weeks later than 

 C. stricta; its dull-colored spikes do not contribute to the 

 general aspect, even though the plant is later and more robust. 

 Garex cephaloidea occupies the margins of the wet meadow 

 formation at a few stations, but at no place is it prominent. 



Gomandra umhellata is the one copious species in the early 

 vernal aspect of the prairie formation. Its general distribu- 

 tion has already been given. Gomandra is a small, rather in- 

 conspicuous, pale green plant with umbels of greenish-white, 

 odorless flowers, and v/ere it not for the aggregation of its 

 individuals and its blossoming at a time when the floral cov- 

 ering is almost destitute of color, it would produce little ef- 

 fect in the floral aspect. As it is, the bastard toad-flax is lost 

 sight of before it has completed anthesis. Gomandra is per- 

 ennial by means of rootstalks, a fact which explains its habit 

 of growing in patches. It is a typical xerophyte. In four- 

 teen quadrats, including various exposures of Great ridge, 

 its numbers range between 400 and 1,900 individuals, the 

 average being 1,000 per quadrat. It is the most abundant of 

 the principal species within the limits of its distribution. The 

 anthers, at least, of the newly opened flowers are frequently 

 in contact with the stigmas by inflection of the filaments, the 



