URDKR 110. CALLITRICHACE^E. 301 



ovate, acuminate, dentate; upper spikes interrupted, leafy at top, sterile, lowei 

 dense, fertile. ii A coarse weed in swamps. 2 3f. Spikes 16'. July, August. 

 ft. lateriflora has narrower leaves, shorter stalks, all alternate. 



12. PARIETARIA, Tourn. PELLITORY. Fls. polygamous, in clus- 

 ters, surrounded by a many-bracted involucre. $ Cal. 4-sepalled. Sta. 4, 

 at first incurved, elastically expanding. $ Stigma tufted. Ach. polished, 

 enclosed within the persistent, 4-lobed calyx. Herbs weed-like, with al- 

 ternate leaves. Clusters of green flowers axillary. 



1 P. Pennsylvania Muhl. Lvs. oblong-lanceolate, veiny, tapering to an obtnse 



point, entire ; involucre longer than the flowers. (I) Rocky shades. 6 12'. 



2 P. Floridana N. Leaves round-ovate, obtuse, entire, on long petioles ; flowers 



as long as the involucre. @ Damp sands, S. 10 7 . (P. debilis Forst. ?) 



13. HUMULUS, L. HOP. Fls. $ S , the $ panicled, with 5 sep. and 

 sta. Anth. with 2 terminal pores. 2 Amenta with large imbricated, en- 

 tire, 1-flowered bracts. Cal. of 1 sepal, investing the acheuium. Styles 2 

 Embryo coiled. J? Twining with the sun. Leaves opposite. Fig. 213. 



II. 1 up ul UK L. Rich alluvion, along streams, and extensively cultivated. Sterna 

 1(K 20f. Leaves cordate, 3-5-lobed, rough, on long stalks. Bitter, narcotic. Jnly. 



14. CANNABIS, Tourn. HEMP. Flowers $ $ , the $ with 5 sep. and 

 sta., in panicles. $ In spikes. Cal. a single spathe-like sepal enfolding the 

 2-valved cariopsis. Embryo curved. Leaves opposite, digitate. 



C. satlva L. Fields, waste grounds. Tall, erect, 4 8f. Leaves petiolate, regularly 

 formed of 5 7 lanceolate-serrate leaflets. Cultivated S-W. Jane. 



ORDER CXV. SAURURACE^E. SAURURADS. 



Herbs with jointed stems, alternate, entire leaves furnished with stipules. 

 Flowers in spikes, perfect, naked, having neither corolla nor calyx. Sta- 

 mens definite. Ovaries 3 5, more or less united. Fig. 15. 



SAURURUS, L. LIZARD-TAIL. Inflorescence a terminal spike of 1- 

 tlowered scales. Sta. 6, 7, 8 or more. Ovaries 4. Berries 4, 1-seeded. It 

 Stem angular. Leaves cordate, acuminate, petiolate. 



S. cernuus Willd. Common in marshes, 1 2f. Leaves 4 6'. Spikes slender, re- 

 curved at the more slender top, its flowers whitish. July, August. 



ORDER CXVI. CALLITRICHACE^E. STARWORTS. 



Herbs aquatic, small, with opposite, simple, entire leaves. Flowers axil- 

 lary, solitaiy, veiy minute, polygamous, achlamydeous, with 2 colored 

 bracts. Stamen 1, rarely 2; filament slender; anther 1-celled, 2-valvcd. 

 reniform. Ovary 4-celled, 4-lobed : ovules solitary. Styles 2 ; stigmas 

 simple points. Fruit 1-celled, 4-seeded, indehiscent. Seeds albuminous. 



CALLITRICHE, L. Character the same as that of the order. 

 Very delicate. 



