400 PLATANACE2E. (PLANE-TREE FAMILY.) 



mum. 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. Pennsylvania, Muhl. (AMERICAN PELLITORY.) 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. CANNABiNE^E. THE HEMP FAMILY. 



10. CAN NAB IS, Toura. 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. SATlvA, L. Waste places, escaped from cultivation. (Adv. from 

 Eu.) 



11. HtlUHJL,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 foliaceous, imbricated, each 2-flowered, in fruit forming a sort of membra- 

 naceous strobile. Calyx of one sepal, embracing the ovary. 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 leaves, 

 and persistent 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. H. Lupulus, L. Banks of streams; not rare, especially westward. 

 July. (Eu.) 



ORDER 105. PLATANACE^G. (PLANE-TREE FAMILY.) 



Trees, with watery juice, alternate palmately-lobed leaves, sheathnxj xtijniles, 

 and moncecious flowers in separate and naked spherical heads, t/< x/ifnte of 

 calyx or corolla; the fruit club-shaped 1-seeded nutlets, furnished with bristly 

 down along the base : consists only of the genus 



1. PIjATANUS, L. PLANE-TREE. BUTTONWOOD. 



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

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



