690 EUPHORBIACEAE 



Order 16. EUPHORBIALES. 

 Herbs, shrubs or trees, sometiraes aquatic or amphibious, but mainly ter- 

 restrial, commonly with a milky juice. Leaves various, sometimes reduced to 

 scales or almost wanting. Flowers mainly monoecious or dioecious, regular. 

 Calyx of several sepals. Corolla of several petals, or often wanting. Androe- 

 cium of more than one stamen, except when the staminate flowers are scattered 

 over the inside of an involucre or in the flowers of Callitriche. Filaments dis- 

 tinct or united into a column. Anthers opening by longitudinal or transverse 

 valves. Gynoecium of 2, 3 or 4 united carpels, superior. Styles or stigmas 

 usually distinct and cleft or foliaceous, united by pairs in Callitrichaceae. 

 OvulesM, 2 or 3 in each cavity. Fruit capsular, sometimes achene-like. Seeds 

 often'carunculate. 



Styles or stigmas distinct or mainly so, cleft or foliaceous : ovary 3-eelled or rarely 1-2-celled : stamens 



several, except when on the inside of an involucre. Fam. 1. Euphorbiaceae. 



Styles united by pairs : ovary 4-celled : stamen solitary. Fam. 2. CALLiTPaCHACEAE. 



Family 1. EUPHORBIACEAE J. St. Hil. Spurge Family. 



Monoecious or dioecious herbs, shrubs or trees, with acrid often milky sap. 

 Leaves opposite, alternate or verticillate, entire or toothed, sessile or petioled, 

 sometimes with glands at the base. Stipules present, obsolete or wanting. In- 

 florescence various. Flowers apetalous or petaliferous, sometimes much re- 

 duced and subtended by an involucre which resembles a calyx {Eujjhorbia and 

 related genera), the number of parts in the floral whorls often different in the 

 staminate and pistillate flowers. Stamens few, or numerous, in one series or 

 many Filaments separate or united. Ovary usually 3-celled. Ovules 1 or 2 

 in each cavity, pendulous. Styles as many as the cavities of the ovary, simple, 

 divided, or many-cleft. Fruit a mostly 3-lobed capsule, separating at ma- 

 turity, often elastically, into 3 2-valved carpels from a persistent axis. Seeds 

 anatropous. Embryo straight, or slightly curved, in fleshy or oily endosperm, 

 the broad cotyledons almost filling the seed-coats. 



A. Flowers not in an involucre : calyx of several sepals. 

 Ovules and seeds 2 in each cavity. 



Monoecious or rarely dioecious : ovary 3-celled ; fruit capsular. 



Stamens 5-6. 1. Andeachne. 



Stamens 2-3. 



Stamens 3 : iilaments partially united. 2. Phvllanthus. 



Stamens 2 : filaments distinct. 3. Reverchonia. 



Dioecious : ovary 1-2-ceHed : fruit drupaceous or^baccate. 4. Deypetes. 



Ovules and seeds solitary in each cavity. 



a. Flowers either staminate or pistillate or both in more or less elongated 

 spikes or racemes ( pistillate basal ) , if clustered on spurs corolla wanting. 

 Corolla present in either staminate or pistillate flowers or in both (except 

 in Croton maritimus). 

 Stamens .5-6 : filaments distinct. 



Filaments 6 : capsules 3-celled, dehiscent. 5. Ckoton. 



Filaments 5 : capsules 1-celled, achene-like. 6. Crotonopsi.s. 



Stamens 10: filaments monadelphous. 7. Ditaxis. 



Corolla wanting. 



Styles 2-3: ovary 2-3-celled. 



Ovary and capsule 2-celled : styles 2 : sepals distinct. 8. Meecuralis. 



Ovary and capsule 3-celled : styles 3 (gynoecium sometimes 2-car- 

 pellary in Sapiinn, but sepals partially united). 

 Stamens numerous, 8-20, rarely few in some flowers. 



Staminate flowers clustered in the axils. 9. Ricinella. 



Staminate flowers in spikes or racemes. 



Stigmas 2-cleft (in our species): pistillate flowers terminal. 10. Bernardia. 

 Stigmas dissected : pistillate flowers axillary. 11. Acalypha. 



Stamens 1-5. 



Pistillate flowers and capsules pedicelled. 



Calyx manifest. 12. Tragia. 



Calyx obsolete or rudimentary. 13. Gymnanthes. 



Pistilhite (lowers and capsules sessile. 

 Receptacle with a central column. 



Fruit dry : seeds witli caruncles. 14. Seb.^^stiana. 



Fruit fleshy : seeds without caruncles. 15. Sapium. 



Receptacle with 3 horns. 16. Stillingia. 



Style> fi-8 : ovarv G-8-celled. 17. Hippomane. 



