EUPHORBIACE^E. ^SPURGE FAMILY.) 385 



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

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

 from novs, foot, and o-Tr\\i.a>v, stamen ; the two stamens being apparently raised 

 on a stalk by the side of the ovary.) 



I. P. ceratopltyllum, 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^]. (Spurge Family.) 



Plants usually u-ith 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. Staminate flowers many (each merely of a single stamen) enclosed in the 



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

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



2. CNIDOSCOLUS. Flowers cymose. Calyx corolla-like, in the staminate flowers salver- 



shaped, 5-cleft Stamens 10 - 15. 

 8. ACALYPHA. 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 3-cleft. Stigmas 3, simple. 

 6. STILLINGIA. 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. PIIYLLANTHUS. Flowers axillary. Calyx 5 - 6-parted. Stamens 3, monadelphous. 



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



1. EUPHORBIA, L. Spurge. 



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

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



33 



