PLATANACEJE. 



SILVA OF NORTH AMERICA. 



101 



Platanus Mexicana^ i^ occasionally used for similar purposes in the cities of northern Mexico; and 

 Platanus occidentalis is sometimes planted in the United States and central and western Europe. 



Platanus in North America is remarkably free from the attacks of disfiguring insects,^ although it 

 suffers from severe fungal diseases.^ All the species of Platanus can be easily raised from seeds^ which 

 germinate the first year, and the varieties can be multiplied from layers or cuttings.^ 



The generic name, the classical name of the Plane-tree, from nXarvg^ was adopted by Tournefort/ 

 and afterward by Linnaeus. 



Mem 



vi. 39, t. 26 {PL Nouv. Am.). 



160. — Hemsley, Bot. BioL Am. Cent. iii. 162. 



XTl 



Mexicana. Jankd 



(1890) 



nervisequumy Saccardo, which attacks Platanus occidentalism Platanus 

 racemosay and the Old World Platanus orientalis. This fungus was 

 first discovered in Germany more than twenty years ago, but its 

 occurrence in the United States was not recognized by botanists 

 until recently. It is now known to be common throughout nearly 



This noble tree, which is planted in the streets of the cities of all parts of the country where Platanus occidentalis and Platanus 

 northwestern Mexico, is distinguished by the thick coat of silvery racemosa grow spontaneously or are cultivated, and to it may per- 

 white tomentum which covers the under surface of the mature haps be referred the cause of the disease of Platanus in the eastern 

 leaves, which, flickering in the wind, make it the most beautiful of states recorded as long as fifty years ago. Its external portion is 



small and not easily recognized except by close observation, appear- 



Plane-trees. 



2 Only a few species of insects are known to live upon the ing in the form of small black spots or lines which lie close to the 



American Plane-trees, and none of them cause serious injuries. veins of the leaves. The disease makes its appearance soon after 



Chalcophora campestriSj Say, lives in the dead wood, and the larvae the leaves have expanded, causing them to turn brown, shrivel, and 



of several moths are occasionally found upon the foliage. Cirrha fall. No practical remedy for it has yet been suggested, for as the 



platanellay Chambers, lives on the under side of the leaves, which mycelium of the fungus is in the leaves and petioles, and probably 



are also fed upon by a number of leaf-miners, including Nepticula also in the younger stems, little benefit can be expected from 



platanella^ Clemens, Nepticula maximella, Chambers, and Nepticula spraying the trees with sulphate of copper or other poisons. A 



Clemensella^ Chambers. A species of Corythuca is sometimes abun- large number of other fungi are found on the trunks and branches 



dant on the leaves, from which it sucks the juices, and a plant- of Platanus, although none of them cause well-defined diseases in 



louse, Lachnus Platanicola^ Kiley, is sometimes foimd on these the United States, 



trees. ** Buc'hoz, Dissertations sur le Cedre du Libauy Le Platane et le 



® The different species of Platanus are peculiarly subject to CytisCyVJ. — GidL^i^Zsvlm^ Notes sur la Culture du Sophoray du Platane 



diseases caused by fungi, several of which produce serious injury, et de VAunCy 18. 



Woodlands 



the most widely spread being caused by the growth of Gloeosporium 



5 Inst. 590, t. 363. 



CONSPECTUS OF THE NORTH AMERICAN SPECIES. 



Leaves broadly ovate, obscurely 3 to 5-lobed, the lobes mostly serrulate-toothed, truncate or rarely 



wedge-shaped at the base. Fruit usually solitary 1. P. occrDENTALis 



Leaves deeply 5-lobed, the lobes entire, remotely and obscurely dentate or rarely sinuate-toothed, 



truncate or rarely slightly cordate or wedge-shaped at the base- Fruit racemose 2. P. racemosa. 



Leaves deeply 3 to 7-lobed, the lobes elongated, slender, entire or rarely remotely dentate, deeply 



cordate or rarely wedge-shaped or truncate at the base. Fruit racemose 3. P. Wrighth. 



