PLANE TREE FAMILY. 389 



9. BROUSSONETIA, PAPER MULBERRY. (Named for P. N. V. 

 Broussonet, a French herbalist.) 



B. papyrifera, Vent. Cult, as a shade tree from N. Y., S.; spreading 

 by suckers, with a very fibrous bark ; leaves rough above, downy beneath, 

 serrate, some of them ovate or slightly heart-shaped, others 3-cleft or 

 variously lobed ; flowering in spring. Japan and adjacent regions. 



10. URTICA, NETTLE. (The classical Latin name.) Common in 

 waste grounds and near dwellings ; flowers summer. 



* Flower clusters in branching panicled spikes ; often dioecious. 2/ 



U. gracilis, Ait. Fence rows, etc., common ; 2-6 high, with ovate- 

 lanceolate, serrate leaves, long petioles, rather few stings, and slender 

 spikes. 



U. diolca, Linn. A weed from Eu., full of stings, 2-3 high, with 

 heart-ovate more deeply serrate leaves, downy beneath and shorter petioles. 



* * Flower clusters shorter than the petiole, mostly 2 in the same axil, 

 containing both sorts of flowers ; stings scattered. (D 



U. tirens, Linn. Weed from Eu., not common ; 8'-12' high, with ovate 

 leaves deeply cut into long spreading teeth ; flower clusters small, loose ; 

 stings few. 



U. chamaedryoldes, Pursh. Slender, with heart-ovate or lance-ovate 

 leaves moderately toothed, and dense flower clusters ; stings sparse. Ky., S. 



11. LAPORTEA, WOOD NETTLE. (Named for M. Laporte. ) ^ 



L. Canadensis, Gaud. Moist and rich woods ; 2-3 high ; ovate 

 leaves 4'-7' long and long-petioled, a single 2n3left stipule in the axil ; 

 flowers all summer. 



12. BCEHMERIA, FAXSE NETTLE. (Named for Pro/. G. B. Boh- 



mer of Germany.) 1J. 



B. cylindrica, Willd. Moist shady grounds, l-3 high, smoothish ; 

 leaves mostly opposite, ovate or lance-ovate, 3-nerved, serrate, long-peti- 

 oled; flower- clusters crowded in long narrow interrupted spikes, in summer. 



B. nivea, Gaud. RAMIE, or the GRASS-CLOTH PLANT of China ; 3-4 

 high, with ovate leaves white-downy beneath ; planted S. for its valuable 

 textile fibers. 



13. PARIETARIA, PELLITORY. (Latin, from its habit of growing 



on walls.) (> 



P. Pennsylvanica, Muhl. Low, only sparingly branched, or simple, 

 minutely downy ; leaves thin and veiny, roughish with opaque dots, 

 oblong-lanceolate. Shady places, Mass., W. and S. 



CVL PLATANACE2E, PLANE TKEE FAMILY. 



This small order consists merely of the genus 



1. PL AT ANUS, PLANE TREE. (The ancient name of the Oriental 

 species, from the Greek word for broad, alluding either to the leaves 

 or the wide-spreading branches.) Flowers monoecious, in separate 

 naked heads hanging on slender peduncles ; the sterile of many short 

 stamens with club-shaped little scales intermixed ; the fertile of club- 



