Book I. 



DISTRIBUTION OF VEGETABLES. 



205 



Sect. V. Systematic Distribution of Vegetables, 



959. The distribution of plants, considered in respect to their systematic classifications, is 

 worthy of notice. The three grand systematic divisions of plants are acotyledoneae, dico- 

 tyledoneae, and monocotyledoneae. A simplification of this division considers plants as 

 agamous, or phanerogamous, that is, without or with visible sexes. 



960. Plants of visible sexes. Taking the globe in zones, the temperate contain \ part 

 of all the phanerogamous or visible sexual species of plants. The equinoctial countries 

 contain nearly 5 \j, and Lapland only ^ part. 



961. Plants with the sexual parts invisible or indistinct. Taking the whole surface of 

 the globe, the agamous plants, that is, mosses, fungi, fuci, &c. are to the phanerogamae 

 or perfect plants, nearly as 1 to 7 ; in the equinoctial countries as 1 to 5 ; in the tem- 

 perate zones as 2 to 5 ; in New Holland as 2 to 1 1 ; in France as 1 to 2 ; in Lapland, 

 Greenland, Iceland, and Scotland, they are as 1 to 1, or even more numerous than the 

 phanerogamous plants. Within the tropics, agamous plants grow only on the summits of 

 the highest mountains. In several of the islands of the Gulf of Carpentaria, having a Flora 

 of phanerogamous plants exceeding 200 species, R. Brown did not observe a single moss. 



962. In the whole globe, the monocotyledonece, including the grasses, liliaceae, scita- 

 mineae, &c. are to the whole of the perfect plants as 1 to 6 ; in the temperate zones 

 (between 36 and 52,) as 1 to 4; and in the polar regions as 1 to 20. In Germany, the 

 monocotyledoneae are to the total number of species as 1 to 4i ; in France as 1 to 4 ; in 

 New Holland the three grand divisions of plants, beginning with the acotyledoneae, are 

 nearly as 1, 2\, and 7\. 



963. Dicotyledoneae. In the whole globe, the monocotyledoneae are estimated, by 

 R. Brown, from Persoon's Synopsis, {Gen. Rem. on the JBot. of Terr. Aust. 1814,) to be 

 to the dicotyledoneae as 2 to 1 1 ; or with the addition of undescribed plants, as 2 to 9. 

 From the equator to 30 of north latitude, they are as 1 to 5. In the higher latitudes a 

 gradual diminution of dicotyledoneae takes place, until in about 60 north latitude and 

 50 south latitude they scarcely equal half their intertropical proportions. The ferns iri 

 the temperate regions are to the whole number of species as 1, 2, and 5 ; that is, in the 

 polar regions as 1, in the temperate countries as 2, and in the intertropical regions as 5. 

 In France, ferns form ^ part of the phanerogamous plants ; in Germany ^ ; in Lap- 

 land 5 l s . 



964. The natural orders of perfect or phanerogamous plants are variously distributed in 

 different countries. The following Table gives a general view of the relative proportions 

 of several natural orders of perfect plants in France, Germany, and Lapland. 



