209 



A good figure of this will be found in the Ann. du Museum, vol. 12. t. 27. 

 fig. E. The germination of Viscum is exceedingly remarkable. It has 

 afforded a subject for some curious experiments upon the nature of the 

 vital energies of vegetables. See Dutrochet sur la Motilite, 114. 



Geography. Judging from the collections of systematic botanists, it 

 would appear that the tropics of America contain a greater number of spe- 

 cies than all the rest of the world ; but we now know, from the extensive 

 researches of Dr. Wallich, that the Flora of India contains at least as large 

 a proportion : the order would therefore seem to be equally dispersed through 

 the equinoctial regions of both Asia and America ; but on the continent of 

 Africa to be much more rare, only 2 having been yet described from 

 equinoctial Africa, and 5 or 6 from the Cape of Good Hope. Two are named 

 from the South Seas, and 1 from New Holland ; but this number requires, no 

 doubt, to be largely increased. 



Properties. The bark is usually astringent, as in the Mistletoe of the 

 Oak. The berries contain a viscid matter like birdlime, which is insoluble in 

 w^ter and alcohol. The most remarkable quality that they possess, however, 

 is the power of rooting in the wood of other plants, at whose expense they 

 live. The habits of the common Mistletoe give an idea of those of all, except 

 that in the genus Loranthus the corolla is tubular and usually richly coloured 

 with scarlet. 



Ex.\MPLEs. Lorauthus,^ Viscum. 



CXCIII. POTALIACEtE. 



PoTALiE^, Martins N. G. et Sp. 2. 91. and 133. (1828.) 



Diagnosis. Monopetalous dicotyledons, with a superior simple ova- 

 rium, regular fluwers, peltate sessile seeds, and a corolla with contorted 

 convolute segments which are unequal to the number of lobes of the calyx. 



Anomalies. 



Essential Character Calyx inferior, with 4, 5, or 6 partitions. Corolla regu- 

 lar, with from 5 to 10 divisions, which are therefore not symmetrical with the segments 

 of the calyx ; the aestivation contorted, convolute. Stamens arising from the corolla, all 

 upon the same line; pollen sim]>le, elliptical. Ovarium superior; style continuous; stigma 

 simple. Fruit succulent, with from 2 to 4 cells, and central placentae. Seeds numerovLS, 

 peltate ; testa double ; embryo supposed by Von Martins to be heterotropous (that is, to 



have its radicle not turned towards the hihim), lying in cartilaginous albumen Trees or 



shrubs, quite smooth. Leaves opposite, entire, united by interpetiolar sheathing stipulae. 

 Flowers terminal, with bractese, in panicles or corymbs. 



Affinities. According to Von Martins, this lies between Logan iese and 

 Apocynea;. Its chief characteristics are the inequality of the segments of the 

 calyx and corolla and the stamens, and a 4-lobed placenta, which produces 

 in Fagrsea obovata, according to Dr. Wallich, a 4-celled berry. With that 

 part of Apocynese to which Strychnos belongs they very nearly agree, differ- 

 ing principally in the above-mentioned character, the aestivation of the calyx, 

 and the embryo not being foliaceous, agreeing in their peltate seeds and cor- 

 neous albumen. 



Geography. Natives of the tropics of Africa, America, and India. 



Properties. An infusion of the leaves of Potalia resinifera is slightly 

 mucilaginous and astringent, and is used in Brazil as a lotion for inflamed 



p 



