100 BOTANY. ' 
most of that India-rubber which comes in bottles. Gum-lac is derived sill 
Aleurites laccifera, a Ceylon plant. 
Euphorbia officinarum, Spurge, Central and South Africa (pl. 71 | fiz Dis 
Euphorbia cyparissias, Central Europe (pl. T1, fig. 8): a and 4, flowers 
of natural size and magnified; c, pistil; d and e, fruit of natural size and 
magnified. | 
Siphonia elastica, caoutchouc tree, South America (pl. 71, fig. 10): A, 
branch with flowers; a, a flower; 6, vertical section of ditto; c, ovary in 
cross-section ; d, ovary ; e, the ripe fruit. 
Orver 56. EmpetTrace#, the Crowberry Family. Flowers unisexual. 
Perianth bud-like, consisting of persistent imbricated scales, in two or four 
alternating rows, the inner row often petaloid. Male flowers; stamens 
two or three, equal in number to the scales in each row, and alternating 
with the innermost, hypogynous ; anthers roundish, dithecal, with longitudinal 
dehiscence. Female flowers: ovary free, fee on a fleshy disk, three- 
to six- or nine-celled; ovules solitary, anatropal, ascending; style one; 
stigma with as many radii as there are ovarian cells. Fruit, a shin 
um, seated within the persistent perianth. Seeds solitary in each nucule, 
ascending ; embryo, in the axis of fleshy albumen; radicle inferior. Heath- 
like shrubs, with alternate or somewhat verticillate, evergreen, exstipulate 
leaves. They inhabit chiefly Europe and North America. The fruit of some 
is slightly acid. Empetrum nigrum, the black Crowberry, is common on the 
mountains and northern parts of Europe, and the United States. The fruit is 
watery, and very slightly acid and astringent. . Lindley notices four genera 
and four species. Examples: Empetrum, Corema. Both these genera have 
North American representatives. 
OrveR 07. Datiscace”, the Datisca Family. Flowers unisexual. Male 
flowers: perianth three- or four-divided. Stamens three to seven; anthers 
linear, membranous, dithecal, with longitudinal dehiscence. Female flowers : 
perianth adherent, three- or four-toothed. Ovary inferior, unilocular ; ovules 
00, anatropal, attached to three or four parietal placentas ; styles, as many 
as the placentas. Fruit, a one-celled capsule, opening at the apex. Seeds 
00, strophiolate, with a reticulated spermoderm ; albumen 0; embryo straight ; 
cotyledons very short ; radicle pointing to the hilum. Herbaceous branched 
- plants or trees, with alternate, exstipulate leaves. They are scattered over 
North America, various parts of Asia, and the south-eastern part of Europe. 
Some of the plants are said to be bitter, and others of them have purgative 
qualities. Lindley mentions three genera and four species. Examples: Da- 
tisca, Tetrameles. 
 Orver 58. RuizanTHeEs, the Rhizogen Family. Flowers usually mone- 
cious or dicecious, sometimes %. Perianth more or less perfect, superior, 
trimerous, tetramerous, or pentamerous ; sometimes obsolete or 0. Stamens 
united, often in a fleshy column, to which the anthers cohere, dithecal, 
extrorse, opening longitudinally or by pores. Ovary inferior, one- or two- 
celled; ovules definite or 00. Fruit indehiscent, pulpy, usually unilocular. 
Seeds, sometimes solitary and pendulous, at other times 00, and attached to 
100 
