240 AMERICAN MIDLAND NATURALIST 
and perhaps P. canadensis under similar conditions would avoid the 
shore, and grow only in deep water. This in itself is a character by 
which the collector may esaily distinguish corresponding aquatic 
forms of each, no matter how much alike: for each species carefully 
selects its habitat. 
I have in my herbarium forms illustrating all the transition 
stages from the normal aquatic to the terrestrial, also plants with 
all the various shapes and kinds of foliage in one specimen. I 
shall therefore not describe the riparian which in this case is a 
plant exhibiting all these transition characters on one individual 
shoot for it may easily be imagined by combining aquatic and 
_ and terrestrial with gradations from one te the other. It is needless 
to say too that aquatic plants are comparatively rare in 
flowering time, in spite of the abundance of flowering terrestrial, 
because of the evident tendency not to bloom in water, and not 
to venture in deep water. Aquatics im fall are found only in wet 
seasons when the water fails to dry up at the shore, or in case o 
an occasional straggling shoot that has ventured just beyond 
the drought line. 
I have selected as types of the aquatic summer phase spec- 
imens No. 965b of my herbarium of which I collected three sheets 
at Millers, Ind., July 9, 1911. At another visit Sept. 21, 1911 
I was unable to obtain typical aquatic plants. Specimens 
showing various transition phases to the terrestrial, 7. e., riparian 
plants, are the following: Nos. 963a, 963b, 963c, 962b, all sub- 
aquatic; 963d, 963e are more terrestrial in appearance, as also 
are 965a, 965e. 965f is subaquatic; 965g is subterrestrial, whereas 
965h and 965] illustrate the last stages of transition to the true 
terrestrial phase represented by 965k and 965]. All these were 
collected at Millers, July 9, 1911. 
Of the aquatics I could not find typical plants in fall, but 
only one straggling depauperate specimen No. 2465 hardly typical, 
and of course with out any apparent tendency to flower. No. 2098 
found the same day, as also No. 2097 1s decidedly transitional to 
the terrestrial, even these being rare at so late a date. Nos. 2465 
and 3001 show the typical fruiting plants with characteristic 
dark purple red, some even bluish-purple or partly blue color 
of the fruiting calyx, as also the closely-flowered broad spikes. 
Flowering specimens in fall are characterized by rose-colored flowers 
(Nos. 2465c, 3003, 2097, 2466). 
