KEY. 271 



89«S. Herbs erect, straight, not twining 896 



Herbs twining. Leaves heart-shaped and 3- to 

 5-lobed, with persistent, ovate stipules between the petioles. 

 Sterile flowers in panicles ; calyx of 5 sepals ; stamens 5. 

 Fertile flowers: aments with several-flowered scales; each 

 flower (pistil) with 1 sepal and embraced by it; styles 2, 

 long. The fertile aments forming in fruit a strobile with 

 large bracts ; achenia invested by the enlarged scale-like 

 calvx. Humulus lupulus, L. 



{Hop.) 



896, Stigmas 2 or 3. Flowers with 3 scarious bracts. 

 Bracts and calyx silvery-white, the latter woolly at the base. 

 Calyx of 5 sepals. Stamens 5 ; filaments slender, united into 

 a short cup at the base ; anthers 1-celled. Leaves petioled, 

 ovate-lanceolate. Panicles narrow. 



(667) Iresine celosioides, L. 

 Style or stigma 1. Flowers not 3-bracted 897 



897, Calyx of the fertile flowers of 2-4 separate or 

 almost separate sepals 898 



Calyx of the fertile flowers urn-shaped, entire, or 2- 

 to 4-toothed, enclosing the ovary; style long, awl-shaped, 

 stigmatic and hairy down one side. Stinging hairs none. 

 Leaves oblong-ovate, or ovate-lanceolate, pointed, serrate, 

 3-nerved. Flowers clustered in axillary spikes. 



(833) Boehmeria cylindrica, Willd. 



898, Herb beset with stinging bristles. Sepals 4 in both 

 sterile and fertile flowers; the 2 inner larger ones enclosing 

 the achenium in fruit. Stigma capitate-tufted. The much- 

 branched spikes longer than the j^etioles, drooping. Leaves 

 ovate-heart-shaped, pointed, deeply serrate. 



Urtica dioica, L. 

 Stinging bristles none. Sterile flowers with 3 or 4 

 sepals and as many stamens. Fertile flowers: sepals 3, 

 lanceolate, slightly unequal, a rudiment of a scale-like sta- 

 men usually before each. Stigma sessile, pencil-tufted. 

 Clustered axillary, scarcely branched spikes much shorter 

 than the petioles, spreading. Leaves ovate, coarsely 

 toothed, pointed, 3-nerved. Stems whitish- or bluish-green, 

 translucent and shining. (833) Pilea pumila, Gr. 



(Richweed.) 



