FLOWERS OF IMP ATI ENS FULVA 145 



specimens was one foot ten inches. The five plants which survived 

 produced only cleistogamous flowers. The failure to produce chas- 

 mogamous flowers may be due to confined rootage, as will be noted 

 below in discussion of further experiments. Several other similar 

 localities were under observation during the summer of 1916. The 

 average height attained by the plants was eighteen inches. They were 

 characterized by the same pale green color, but seemed healthy and pro- 

 duced abundant cleistogamous flowers, but few chasmogamous flowers. 



Short-stemmed plants are produced also in situations where the 

 soil moisture is below the optimum for the species. At the top of the 

 hill, above the plants just referred to, in an open woodland one such 

 group of plants has been under observ^ation for two years. During 

 May and June the soil is quite moist, but in mid and late summer the 

 soil becomes decidedly dry. During June and early July in both years, 

 these plants were in good condition. They were of a darker green than 

 the bog plants noted above, and some showed some evidence of the 

 ruddy stems characteristic of the species. These produced abundant 

 cleistogamous flowers during June, and moderately abundant chas- 

 mogamous flowers in July. They were killed by dry weather in August. 

 The average height of these plants was two feet, and none were observed 

 over two feet seven inches. Similar groups of plants in other sunny 

 situations, where the soil was somewhat dry, were observed in fair 

 abundance, averaging two feet or less in height. 



Under the most favorable conditions relatively enormous heights 

 are attained. The optimum conditions for vegetative growth seem to 

 be found along brooks in rather open woodlands, with the roots of the 

 plants washed by the running water. Under these conditions, plants 

 six feet in height were found. The tallest plant measured in the vicinity 

 of Philadelphia was six feet four inches in height. The stems and 

 branches of these plants were a dense reddish color. The plants at- 

 tained a circumference of over six inches near the base, and were but- 

 tressed by series of adventitious roots growing from the lower two or 

 three nodes above the ground. Dr. Macfarlane reports plants of the 

 species on Peak's Island, Maine, attaining a height of seven feet, and 

 seven feet five inches. These plants were growing upon a sloping bank 

 facing the sea. The abundance of percolating moisture and the open 

 gravelly soil probably account for the enormous growth. 



The habitat given by the Manuals for this species is moist shady 

 places, in rich ground. The species is abundant, however, not only 

 in this habitat but also in more sunny and drier locations. The optimum 



