Euphorbia.] LXVIII. EUPHOKBIACEiE. 391 



Several male flowers (looking like single stamens) and one 

 stalked ovary collected in a small involucre, which has the 



appearance of a cup-shaped perianth 1. Euphorbia. 



Male and female flowers distinct. 



Herbs, with thin leaves 2. Mercurialis. 



Shrubs, with shining, evergreen leaves 3. Buxus. 



The Poinsettia and the red-flowered Jatrophas of our hothouses 

 remarkable for their brilliant red bracts, and the coloured leaved 

 Crotons, belong to this family, but generally speaking the tropical 

 Euphorbiacece are not ornamental enough for cultivation. 



I. EUPHORBIA. SPURGE. 



The European species are herbs, abounding in milky juice ; the lower 

 part of the stems simple, with alternate leaves (except in E. Lathyris). 

 Flowering branches or peduncles axillary, the upper ones in a terminal 

 umbel of 2 to 5 or more rays, each ray or axillary peduncle usually 

 several times forked, with a pair of opposite floral leaves at each fork, 

 and a small green, apparent flower, really a head of flowers, between 

 the branches. These flower-heads consist of a small, cup-shaped involucre 

 (looking like a perianth), with 4 or 5 very small teeth, alternating with 

 as many horizontal yellowish or brown glands. Within are 10 to 15 

 stamens, each with a jointed filament, and a minute scale at its base, 

 showing that they are each a distinct male flower. In the centre is a 

 single female flower, consisting of a 3-celled ovary, supported on a stalk 

 projecting from the involucre and curved downwards. Style 3-cleft. 

 Fruit of 3 carpels, each with a single seed. 



A very large genus, extending over most parts of the globe, including 

 many tropical species, and leafless, succulent ones in southern Africa. 



Prostrate plant, with all the leaves at the time of flowering 



floral and opposite, with minute stipules . . . . 1. E. Peplis. 

 Stem erect or decumbent at the base, the lower leaves alternate, 

 and no stipules. 

 Glands of the involucre rounded on the outer edge. 

 Annuals or biennials. Leaves finely toothed. 

 Leaves obovate, very obtuse. Capsules smooth . . 2. E. Helioscopia. 

 Stem -leaves oblong, usually pointed. Capsules more or 



less warted 3. E. platyphyllos. 



Perennials. Leaves entire. 

 Umbel compact. Capsule glabrous, much warted . . 4. E. hiberna. 

 Umbel loose. Capsule smooth, or rough with small 



glandular dots, often hairy 5. E. pilosa. 



Glands of the involucre crescent-shaped, the two points turned 

 outwards. 

 Floral leaves of each pair united at the base . . 12. E. amygdaloides. 



Moral leaves all distinct. ' 

 Umbel of 3 or 4 rays. 

 Low, green annuals, seldom above 6 inches high. 



Stem-leaves linear 7. E. exigua. 



Stem-leaves broadly obovate, stalked . . . . 6. E. Peplus. 

 Tall, very glaucous biennial, with large capsules . . 8. E. Lathyris. 

 Umbel of 5, rarely 6, rays. 

 Leaves crowded, thick and leathery. Umbel compact. 



Seeds smooth 10. E. Paralias. 



Leaves rather thin. Umbel spreading. Seeds pitted . 9. E. segetalis. 

 Umbel of 8 or more rays 11. E. Esula. 



