EUPHORBIACE^. (^SPURGE FAMILY.) 385 



Pod oval, 8-ribbed, 2-celled, 2-valved. Seeds minute, very numerous on a thick 

 persistent central placenta, destitute of albumen. Leaves 2-ranked. (Name 

 from TroCy, foot, and OTI^COI/, stamen ; the two stamens being apparently raised 

 on a stalk by the side of the ovary.) 



1. P. ceratophylluni, Michx. Leaves rigid, dilated into a stipule- 

 like sheathing base, above mostly forked into thread-like or linear lobes. Not 

 uncommon in the bottom of shallow streams. July- Sept. A small olive-green 

 plant, of firm texture, resembling a Sea-weed, tenaciously attached to loose 

 stones, in the manner of a Fucus, by fleshy disks or processes in place of roots. 



ORDER 102. EUPHORBIACE.E. (SPURGE FAMILY.) 



Plants usually witli a milky acrid juice, and various, usually monoecious or 

 dioecious flowers ; the fruit of 2 - 3 or several 1 - 2-seeded pods united around 

 a central axis, separating when ripe (rarely of a single pod). Seed suspend- 

 ed, anatropous. Embryo with flat cotyledons nearly as long as the albu- 

 men. Stigmas 2 - 3 or more, often forked. Calyx usually valvate in the 

 bud, occasionally wanting. Petals sometimes present. A large family in 

 the warmer parts of the world (the acrid juice poisonous) ; most numer- 

 ously represented in Northern countries by the genus Euphorbia, which 

 has very remarkable reduced flowers enclosed in an involucre that imitates 

 a calyx; and sparingly by a few other genera: the tribes not yet well set- 

 tled. The proper place for the order is in the Polypetalous division. 



Synopsis. 



* Seeds and ovules only one in each cell. 



- Staminate and pistillate flowers, both destitute of calyx as well as corolla, and contained In 

 the same cup-shaped involucre, which resembles a calyx. 



1. EUPHORBIA. Stamiuate flowers many (each merely of a single stamen) enclosed in the 



involucre, the single pistillate flower projecting from it on its stalk. Pod 3-lobed. 

 t- -i- Flowers (monoecious) of both kinds with a calyx, but no petals, not in an involucre. 



2. CN1DOSCOLUS. Flowers cyinose. Calyx corolla-like, in the staminate flowers salver- 



shaped, 5-cleft Stamens 10 - 15. 

 8. ACALYPIIA. Flowers spiked and glomerate. Stamens 8 - 16 : filaments monadelphous at 



the base. Styles capillary-dissected. 



4. TRAGIA Flowers in racemes. Stamens 2 or 3. Style 8-cleft. Stigmas 3, simple. 

 6. STILLINQIA. Flowers in a terminal spike. Stamens 2. Stigmas 3, simple. 

 - -^ - Flowers (monoecious) of both kinds with a regular calyx, and at least the staminate 

 with petals also, not in an involucre. 



6. CROTON. Flowers spiked or glomerate. Ovary and fruit 3- (rarely 2-) celled. 



7. CROTONOPSIS. Flowers scattered on the branchlets, axillary. Ovary and fruit 1-celled. 



* * Seeds and ovules 2 in each cell. (Calyx present, but no petals. ) 



8. PHYLLANTHUS. Flowers axillary. Calyx 5-6-parted. Stamens 3, monadelphous. 



9. PACIIYSANDHA. Flowers spiked. Calyx 4-parted. Stamens 4, separate. 



1. EUPHORBIA, L. SPURGE. 



Flowers monoecious, included in a cup-shaped 4-5-lobed involucre (flower of 

 older authors) resembling a calyx or corolla, usually bearing large and thick 

 33 



