102 FAMILIES OF FLOWERING PLANTS 
All the transition stages of this process may be observed in the flower 
of the common water-lily. This genus (Castalia) is represented in the 
United States by several species. The flowers of C. odorata are the 
most fragrant; in southern species the fragrance partially or wholly 
disappears. On the coast of New England, particularly on Cape Cod, 
occurs a beautiful pink-flowered variety. The exotic Castalias, usually 
cultivated as Nymphaeas, exhibit a wide diversity of coloration, includ- 
ing all shades of blue, purple and red. The yellow lotus (Nelumbo 
lutea) is common in certain parts of the country, while the pink lotus 
(N. Nelumbo) has become natural- 
ized in ponds about Bordentown, 
New Jersey. The giant water-lily 
of the Amazon (Victoria regia) is too 
well known by description to require 
comment. 
Family Ceratophyllaceae. Horn- 
wort family. Contains a single 
genus, Ceratophyllum, with three 
widely distributed species, the most 
familiar of which is C. demersum. It 
is a submerged aquatic, with capil- 
lary or thread-like stems and leaves, 
found frequently in slow-moving 
streams. The flowers are without a 
corolla, and the calyx is many- 
parted. The fruit is an achene with 
a long beak, and usually covered 
with tnbercles or provided with 
spiny appendages. 
Fig. 85. The marsh marigold (Caltha pa- Family Trochodendraceae. Tro- 
Justris). After Britton & Brown, Ill. Fl. chodendron Family. Contains two 
North. U. 8. «ze . 
genera, Cercidiphyllwm, with two spe- 
cies, and Trochodendron, which is monotypic. They are Japanese trees, 
formerly included in the Magnoliaceae, but distinguishable on account of 
their peculiar flowers, which are entirely destitute of perianth. The 
numerous stamens are deciduous, surrounding the 5-8-celled ovary. The 
leaves are borne in whorls, a character from which the names of both 
venera are derived. 
Family Ranunculaceae. Crowfoot or Buttercup Family. Con- 
tains about 40 genera and over 1000 species, natives of temperate or 
even arctic regions, remarkably scarce in the tropics. They are herbs 
or rarely climbing shrubs, with watery and acrid juice, simple or com- 
pound leaves, and flowers usually with both calyx and corolla, the 
