KEY. 255 



dehiscent into 3 or 2 carpels. Sterile flowers with a 5-parted 

 calyx, 5 petals, and 5-12 stamens, on a 5-tubercled (glandu- 

 lar) disk. Fertile flowers without petals and with a 5- or 8- 

 lobed calyx. Leaves entire. (804) Croton. 



(§ Pilinophytum, Klotzsch, 



et 



§ Gynaniblosis, Torr.) 



Flowers scattered on the branches, axillary on them, 



minute, the upper sterile. Stigmas 3, 2-cleft. Ovary 1-cell- 



ed, 1-seeded. Pod indehiseent. The sterile flowers with 5 



perfect, the fertile with 5 rudimentary scale-like stamens — the 



calyx of the former 5-, of the latter 3- to 5-parted. Petals 



none in the fertile flowers. Leaves silvery-hoary. 



Crotouopsis linearis, Mx. 



809. (799.) A maritime herb. Flowers naked, the ste- 

 rile alternating with the fertile on the inner side of the 

 linear, flat spadix, enclosed by a spathe. Anther 1, sessile. 

 Ovary with a bifid style. Leaves grass-like, entire, obtuse. 



Zostera marina, L. 

 ((Sea- Wrack.) 



Terrestrial, or fresh-water herbs 810 



810. Herbs with terminal, cylindric, club-shaped, or 

 globular heads, bearing a multitude of crowded flowers, 

 with not any or a very doubtful perianth (bristles, scales). 

 Stamens innumerable, or rarely whorls of them attributable 

 to the several sterile flowers 811 



Flerbs with flowers having, at least the sterile ones, 

 a true, simple perianth, or some obvious substitute of it ; or 

 herbs with glumaceous (grass-like) blossoms. Stamens def- 

 inite. Flowers sometimes many on a common receptacle. 



815 



811. Spadix enclosed in a spathe 812 



Spadix without a spathe 814 



813. Flowers covering the base of the spadix. j 



(550) Arissema (903). 

 Flowers covering the whole spadix 813 



813. The lowest flowers of the spadix perfect. Spathe 



open. (550) Calla. 



The upper flowers of the spadix staminate, the 



