EUPHORBIA, SECTION TITHYMALUS. 89 
lines shows in some degree the probable distance of rela- 
tionship; and as nearly as possible apparently related species 
of different groups have been approximated. 
For morphological works see Warming, Er Koppen hos 
Vortemaelken en Blomst eller en Blomsterstand? Kob- 
enhavn. 1871; and Eichler, A. W. Bliithendiagramme 
2: 386-392. 1878. 
For anatomical works see Pax, F. Die Anatomie der 
Euphorbiaceen in ihrer Beziehung zum System derselben. 
Engler’s Bot. Jahrb. 5 : 384-421. pl. 6, 7. 1884; and Pam- 
mel, L. H. On the Seed-coats of the Genus Euphorbia. 
Trans. Acad. Sci. St. Louis 5: 343-368. pl. 12-14. 
1891. 
For works on distribution, etc., see Bentham, G. Notes 
on Euphorbiaceae. Journ. Linn. Soc. Bot. 17: 185-267. 
1880; and Krinzlin, Die Verbreitung der Arten der Gat- 
tung Euphorbia. Progr. 39. Berlinisches Gymnasium zum 
grauen Kloster. 1876. 
For works on medicinal and economic properties see 
Dragendorf,G. Die Heilpflanzen 385-391. 1898; and 
Millspaugh, C. F. Medicinal Plants 2: 147-150. 1892. 
Evrenorsia Linn. Sp. Plant. 450. 1753. 
§ TrruymaLus. The floral leaves opposite, the others 
usually alternate, exstipulate; inflorescence cymose 
umbellate; glands exappendiculate. 
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