(273) 



1. Platanus L. SYCAMORE. 

 Only genus. . 

 1. P. RACEMOSA Nutt. Common. Spring. 



Family 2, URTICACE^. 



<3 perigonium 4-lobed; stamens 4; fila- 

 ments inflexed in aestivation; anthers introrse, 

 2-celled; ovary rudimentary. ? perigonium 

 2 to 4-lobed; ovary 1-celled, 1-ovulate; fruit 

 an akene, sometimes baccate by the persistent 

 and succulent perigonium. Stipules generally 

 persistent. 



1. Urtica To urn. NETTLE. 



$ perigonium regular and spreading. ? 

 perigonium 2-parted, with sessile, penicillate 

 stigma. Herbs covered with stinging hairs. 



1. U. HOLOSERICEA Nutt. Inflorescence uni- 

 sexual; petioles short, stout. 2f. Common. 

 Summer. 



2. U. LYALLII Watson. Inflorescence uni- 

 sexual; petioles long, slender. if. Marin 

 County. Summer. 



3. U. URENS L. Inflorescence androgynous. 

 . Cultivated lands. Spring. 



Introduced from Europe. 



2. Hesperocnide Torr. 



$ perigonium gamophyllous, urceolate, com- 

 pressed, minutely dentate. 0. 



12A 



