350 BIONOECIA.— TETRANDRIA, 



TETRANDRIA. 



535. ERIOCAULON. Pipewort. Resliacea>, 



t. E. pellucidum : scape slender, about 7-furrowed : 

 leaves linear-subulate, canaliculate, smooth, pel- 

 lucid, 5-nerved, transversely striate ; head small, 

 globose ; scales of the involucrum oval, obtuse. 

 HAB. Water. June. U. Scape 4 — 6 in. high; 

 leav. rad., cesp. ; Jl. white. 



2. E. decangulare : scape 10-furro\ved ; leaves ensi- 

 forrn, smooth ; head large, hemispherical ; scales 

 of the involucrum oval, acute ; of the receptacle 

 mucronate. 

 HAB. Water. Aug. Scape 2 — 4 ft. high ; leav, 

 without midrib ; Jl. wh. 



536. ALNUS. Alder. Salicince. 



1. A. serrulata : leaves obovate, acuminate, with the 



veins and their axils hairy underneath ; stipules 

 elliptical, obtuse. 

 HAB. Low grounds. Blarch — Apr. Shrub 8 — 15 

 ft. high, much branch. 



2. A. undulata : leaves oblong, acute, rounded at the 



base, doubly serrate ; petioles and the veins be- 

 neath L.ury ; axils of the veins naked ; stipules 

 ovate-c'dong. 

 HAB. Mountain swamps. April. Shrub 3 — 4 ft. 



high. 



537. BOEHMERIA. Urticece. 



B. cylindrica : leaves opposite, ovate-oblong, acu- 

 minate, dentate, smooth ; flowers dioecious ; ste 

 rile spikes glomerate, interrupted ; fertile cylin- 

 drical ; stem herbaceous. 



HAB. Shady swamps. July — Aug. U. Stem 

 slend., 2 ft. high ; leav. petiol.; Jl. minute. 



B. lateriflora : leaves alternate, ovate-lanceolate ; 

 acuminate, serrate, scabrous ; stem herbaceous. 



HAB. Woods. July. 1*. Stem smooth; leav. 

 scabrous on both surfaces. 



