400 PLATANACE^. (PLANE-TREE FAMILY.) 



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

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

 European species often grow.) 



1. P. PcnnsylvSinica, Muhl. (American Pellitort.) 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. CANIVABINEJE. The Hemp Family. 



lO. CANNABIS, 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. SAiivA, L. — Waste places, escaped from cultivation. (Adv. from 

 Eu.) 



11. HtrM:iJL,tJS, L. Hop. 



Flowers dioecious ; the stei-ile 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. liUpnlns, L. — Banks of streams; not rare, especially westward. 

 July. (Eu.) 



Order 105. PLATANACE^. (Plane-teee Family.) 



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

 and monoecious flowers in separate and naked spherical heads, destitute of 

 calyx or corolla; the fruit club-shaped 1-seeded nutlets, furnished uiith hrktly 

 down along the base : consists only of the genus 



1. PIiATAJVUS, L. Plane-tree. Buttonwood. 



Sterile flowers of numerous stamens with club-shaped little scales intei-mixed ; 

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



