428 CALLITRICHACE^E. (WATER-STAR WORTS.) 



senting the most reduced form of the Halorageae, p. 1 74. The so-called 

 perfect flower is considered to be a staminate and a pistillate, or two stam- 

 inate and one pistillate naked flowers in the same axil, each of a single 

 stamen or pistil.) 

 The elaboration of our species is contributed by DR. G. ENGELMANN. 



1. CALLITBICHE, L. WATER-STARWORT. 



Flowers monoecious, solitary or 2 or 3 together in the axil of the same leaf, 

 wholly naked or between a pair of membranaceous bracts. Sterile flower a sin- 

 gle stamen : filament bearing a heart-shaped 4-celled anther, which by confluence 

 becomes one-celled, and opens by a single slit. Fertile flower a single 4-celled 

 ovary, either sessile or pedicelled, bearing 2 distinct and filiform sessile, usually 

 persistent stigmas. Ovule solitary in each cell. Fruit nut-like, compressed, 4- 

 lobed, 4-celled, separating at maturity into as many closed 1-seeded portions. 

 Seed anatropous, suspended, filling the cell : embryo slender, straight or slightly 

 curved, in the axis and nearly the length of the oily albumen. Smooth, or beset 

 with minute stellate scales (visible only under the microscope), with spatulate or 

 linear leaves, both forms often occurring on the same stem. (Name from KaXos-, 

 beautiful, and 6pi, hair, from the almost capillary and usually tufted stems of 

 the commoner species.) 



1. TERRESTRIAL SPECIES. Small annuals, forming tufts on merely moist soil ; 

 destitute of stellate scales and of bracts : leaves uniform, very small, obovate or 

 wedge-shaped '/ 3-nerved, crowded, provided with stomata : filament not lengthen- 

 ing : carpels connate. 



1. C. Austin!, Engelm. Fruit small, broader than high, deeply notched 

 above and below, on a pedicel often nearly of its own length ; lobes of the fruit 

 narrowly winged and with a deep groove between them, wings denticulate ; per- 

 sistent stigmas shorter than the fruit, spreading or reflexed ; leaves obovate. 

 On damp soil in open woods, fields and roads, New York and New Jersey ( C. F. 

 Austin) to Illinois, Missouri, Texas, Mexico, and South America. April- June. 

 Half an inch or an inch high : leaves 1" - 2"'long : fruit J" in diameter. 



C. PEPLOIDES, Nutt. and C. NUTTALLII, Torr. (C. pedunculosa, Nutt.), 

 the former with subsessile curiously gibbous fruit, the latter with long-peduncled 

 fruit with eversed keels, are southwestern species of this section. 



2. AMPHIBIOUS SPECIES. Perennials ? with elongated stems (occasionally quite 

 terrestrial as in the former, or wholly submersed as in the next section) : leaves 

 with stellate scales and stomata, the floating ones obovate and 3-nerved, the sub- 

 mersed linear: flowers usually between a pair of bracts, rarely naked: pollen shed 

 only in the air ; the filament elongating afterwards: carpels in fruit connate. 



2. C. verna, L. Fruit (|-" long) higher than broad, obovate, slightly ob- 

 cordate, usually thicker at the base than upwards, sessile, its lobes sharply keeled 

 or very narrowly winged upwards, and with a wide groove between them ; stig- 

 mas shorter than the fruit, almost erect, usually deciduous ; floating leaves 

 crowded in a tuft, obovate, narrowed into a petiole. Common in stagnant 

 waters, from Pennsylvania and New Jersey north and northwestward. April - 



