206 APPENDIX. 



teresting, not alone on account of the striking contrasts they bring out, but also as 

 showin- that the general composition of the vegetation is almost equally varied in the 

 two regions. The orders without bracketed numbers before them, in the preceding 

 Table where not otherwise explained, are not represented in. Australia ; but after 

 adding five that are treated as suborders or tribes of others by Mueller, and one acciden- 

 tally omitted by him, the total in Australia is 154 against our 167. Twenty-nine of 

 the Mexican orders are not represented in Australia, as opposed to sixteen in which 

 the condition is reversed. Grisebach's materials gave the following sequence in the 

 West Indies:— Leguminosae, Orchidea?, Eubiaceae, Composite, Euphorbiaceee, Grainmeae, 

 Melastomaceee, Cyperacese, Urticaceae, Myrtaceae, Solanaceae, and Convolvulaceae. Apart 

 from the Cactacese the sequence of the first twenty-five orders in Mexico and Central 

 America combined approaches closely to that of the same orders in the flora of the 

 whole world, as maybe seen from the following list of the twenty-five largest orders:— 

 Composite Leguminosa3, Orchideee, Eubiaceae, Gramineae, Euphorbiacese, Labiatae, 

 Cyperaceae, Liliacea*, Scrophularinea?, Myrtaceae, Melastomaceae, Urticaceae, Acanthaceae, 

 Asclepiadeae, Umbelliferae, Solanaceae, Cruciferae, Boraginese, Palmae, Campanulacea., 

 Ericaceae Cactaceae, Eosaceae, Piperacea3. According to the roughly-estimated numbers 

 of species in Bentham and Hooker's * Genera Plantarum,' the first of these orders 

 comprises about 10,000 species, and the last about 1000. Turning to the first twenty- 

 five orders in Australia we find that at least one-third of them are not of general 

 distribution, and thirteen of them are different from those just named. The Australian 

 sequence of the first twenty-five is :— 1, Leguminosae; 2, Myrtaceae; 3, Proteaceae ; 

 4, Composite ; 5, Cyperaceae ; 6, Gramineae ; 7, Orchideae ; 8, Epacrideae ; 9, Euphor- 

 biaceas; 10, Goodeniacese ; 11, Filices; 12, Eutaceae; 13, Liliaceae; 14, Eubiaceae; 

 15, Labiataa; 16, Sterculiaceaa ; 17, Chenopodiaceae ; 18, Malvaceae ; 19, Umbelliferae ; 

 20, Sapindaceae; 21, Amarantacese ; 22, Dilleniaceae ; 23, Stylideae ; 24, Eestiaceae ; 

 25, Ehamnaceae. Similar divergences are met with on carrying the comparison further ; 

 and we perceive that, notwithstanding the great richness and diversity of the Mexican 

 flora, it is by no means so highly specialized as the Australian ; yet more so than is 

 apparent from this comparison, because the characteristically Mexican physiognomical 

 types do not happen to run so much in orders as in genera. This obtains, though of 

 course not to the same extent, even when the flora of Central America is left out of 

 consideration. Some further observations on this and cognate points will be found in 

 the discussion of the endemic element. The comparatively low position of the 

 Composita? in the Australian flora is one of its most remarkable features. In all the 

 five floral regions of extra-tropical South Africa, proposed by Bolus*, Compositae 

 predominate, and in some of them very largely; reaching as high as 23*6 per cent, in 



* Sketch of the Flora of South Africa, in the official Handbook of the Cape of Good Hope for the Colonial 

 and Indian Exhibition, 1886. 



