PEN -ANDRIA MONOGYNIA. 1 



P. diversifolium : upper leaves floating, elliptical, petiolate, 5-nerveU ; 

 inferior ones filiform ; spike axillary, almost sessile, few-flow- 

 ered. 



HAB. Ponds and slow streams. June. C ; Stems filiform upper 

 leaves not an inch long spikes 4 6-Jlowered. 



* * Leaves all submerged. 



P. perfoliatum: leaves amplexicaul, cordate, ovate. 



HAB. Rivers and lakes. August. Stem dichot. leaves 1 inch long, 

 subpelluc. spike few-Jloicers. 



P. lucens : leaves ovate-lanceolate, petiolate. 



HAB. Rivers and lakes. August. CStem terete leaves 2 3 

 inches long, pelluc. reticulated spikes cylindrical. 



P. crispum : leaves lanceolate, tapering, sessile, undulate and ser- 

 rate. 



HAB. Lakes. August. C; Stem subcomp. leaves 1J inches long 

 spikes 8 lO-^o we red. 



P. pectinaceum: leaves setaceous, distichously approximate, sheath- 

 ing ; stipules almost wanting ; spike few-flowered, interrupted. 



HAB. Ponds. June. C; Stem filif. dichot, leaves numerous 

 4 6 inches long peduncles elongated. 



PENTANDRIA. 

 MONOGYNIA. 



A. Seeds naked. (AsFERlFOLlJE.) 

 Genera. * Seeds fixed to the bottom of the calyx. 



8. LITHOSPERMUM. Calyx 5-parted ; segments acute, cannate; 

 corolla infundibuliform ; border 5-lobed ; orifice naked; stem includ- 

 ed within the tube of the corolla ; stigma obtuse, bifid ; seeds imper- 

 forated at the base, indurated, shining. 



89. ONOSMODIUM. CaZy.r deeply 5-parted; segments linear; corolla 

 subcampanulate ; border ventricose, half 5-cleft ; segment connivent, 

 acute ; orifice naked ; style much exserted ; seeds ovate, shining, im- 

 perforate at the base. 



90. ECHIUM. Ca ly x 5-parted ; segments subulate, erect ; corolla sub- 



campanulate ; tube very short ; border unequally 5-lobed, the lower 

 segment acute and reflexed ; orifice pervious ; stigma bifid ; seeds 

 tuberculate, imperforate at the base. 



91. MYOSOTIS. Calyx 5-parted, or 5-cleft ; corolla hypocrateriform ; 

 segments very obtuse ; orifice closed with connivent scales. 



92. LYCOPSIS. Calyx 5-cleft ; corolla infundibuliform ; orifice closed 

 with ovate, connivent scales ; seeds perforated at the base. 



