400 PLATANACE^E. (PLANE-TREE FAMILY.) 



nium. Stigma pencil-tufted. Small homely herbs, chiefly with alternate 

 leaves ; not stinging. (Name from paries, a wall ; from the places where the 

 European species often grow.) 



1. P. IV'imsylvaiiicu, Muhl. (AMERICAN PEI.LITORY.) Low, an- 

 nual, simple or sparingly branched, minutely downy ; leaves oblong-lanceolate, 

 very thin, veiny, roughish with opaque dots ; flowers shorter than the leaves of 

 the involucre ; stigma sessile. Shaded rocky banks, Vermont to Wisconsin 

 and southward. June - Aug. 



SUBORDER IV. CANftABIftEJE. TIIE HEMP FAMILY. 



1O. <'A ft ft A It IS, Tourn. HEMP. 



Flowers dioecious ; the sterile in axillary compound racemes or panicles, with 

 5 sepals and 5 drooping stamens. Fertile flowers spiked-clustered, 1-bracted : 

 the calyx of a single sepal swollen at the base and folded round the ovary. 

 Embryo simply curved. A tall roughish annual, with digitate leaves of 5-7 

 linear-lanceolate coarsely toothed leaflets, the upper alternate ; the inner bark of 

 very tough fibres. (The ancient name, of obscure etymology,) 



1. C. SAT!VA, L. Waste places, escaped from cultivation. (Adv. from 

 Eu.) 



11. HIJNIUI.US, L. HOP. 



Flowers dioecious ; the sterile in loose axillary panicles, with 5 sepals and 5 

 erect stamens. Fertile flowers in short axillary and solitary spikes or catkins : 

 bracts foliaccons, imbricated, each 2-flowered, in fruit forming a sort of meinlira- 

 naceous strobile. Calyx of one sepal, embracing the ovarv. Achenia invested 

 with the enlarged scale-like calyx. Embryo coiled in a flat spiral. A rough 

 perennial twining herb, with mostly opposite heart-shaped and 3-5-lobed leaver, 

 and prrsistent ovate stipules between the petioles. Calyx-scales in fruit covered 

 with orange-colored resinous grains, in which the peculiar bitterness and aroma 

 of the hop reside. (Name thought to be a diminutive of humus, moist earth, 

 from the alluvial soil where the Hop spontaneously grows.) 



1. II. IL up ul us, L. Banks of streams; not rare, especially westward. 

 Ju'y. (Eu.) 



ORDER 105. PLATANACE7E. (PLANE-TREE FAMILY.; 



Trees, with watery juice, alternate palmately-lobed leaven, sheathing stipules, 

 and monoecious flowers in separate and naked aj,Ji.erical leads, destitute of 

 calyx or corolla; the fruit club-shaped \-seeded nutlets, furnished with brixtly 

 down along the base : consists only of the genus 



1. PI, AT A ft US, L. PLANE-TREE. BUTTON WOOD. 



Sterile flowers of numerous stamens with club-shaped little scales intermixed 

 filaments very short. Fertile flowers in separate catkins, consisting of inversely 



