loBIMONIA.] ROSACES. 119 



i-lunate. Racemes lengthening and pedicels recurved in fruit ; bracts 3-fid ; 



Sracteoles close to the calyx. Flowers ^ in. diam. Calyx-tube 1- in., woody 



in fruit, spines many around the thickened mouth ; segments conniving, 



triangular, acute. DISTKIB. N. temp, regions, N. and S. Africa. Rootstock 



astringent, and yields a yellow dye. 

 Sub-sp. EUPATO'RIA proper ; calyx -tube obconic deeply furrowed, lower spines 



spreading. 

 Sub-sp. ODORA'TA, Mill, (sp.) ; more branched, resinous-scented, racemes 



denser, flowers larger, calyx-tube campanulate scarcely furrowed, lower 



spines spreading or reflexed. From Westmoreland southwards to Jersey, 



local ; very rare in Ireland. 



10. POTE'RIUM, L, 



Erect perennial herbs. Leaves pinnate; leaflets stalked; stipules ad- 

 nate to the sheathing petiole. Flowers small, sabsessile, in deuse long- 

 peduucled heads or centrifugal spikes, bracteate, 2-bracteolate, often poly- 

 gamous. Calyx-tube persistent, turbinate, mouth contracted ; lobes 4, 

 jK'taloid, deciduous, imbricate in bud. Petals 0. Stamens 4 or more, 

 iiisrrii'd at the mouth of the calyx, filaments slender pendulous. Disk 

 lining the calyx-tube and closing its mouth. Carpels 13, enclosed in 

 the calyx-tube ; styles filiform, stigma penicillate ; ovule 1, pendulous. 

 Acheiws solitary, enclosed in the hardened 4-angled often winged or 

 muricate calyx-tube. DISTUIB. N. temp, regions ; species 20. ETYM. 

 obscure. 



1. P. Sanguisor'ba, L.; upper flowers of each head female, lower 

 male or 2-sexual, stamens 20-30 much exserted, fruiting calyx 4-wingetl 

 reticulate but not pitted between the wings, edges of reticulation smooth. 

 Hilxd Burnet. 



Dry pastures, from Perth and Forfar southwards ; ascending to 1,600ft. in 

 Yorkshire ; rarer in Scotland and in Ireland ; fl. June-Aug. Erect or 

 decumbent, 6-18 in., glabrous or nearly so, slender, much branched. Root- 

 stock stout. Radical leaves 4-10 in.; leafbts 5-10 pair, -f in., petioled, 

 broadly oblong, coarsely serrate ; stipules leafy. Flower-head* ^-% in., on 

 long peduncles, shortly oblong, purplish. Calyx-Mies ,' in., oblong ; wings 

 thin; bracteoles ciliate. Stiynuis exserted. Actetied&rk, striate. DISTEIB. 

 Europe, N. Africa, Siberia. 



P. MURICA'TUM, Spm-h ; flower-heads and flowers as in P. Sanguisorba, 

 but fruiting calyx with thick entire or toothed wings, pitted and reticu- 

 lated between the wings, ridges muricate and toothed. 



Cultivated ground in Mid. and S. England ; an alien or colonist, Watson ; fl. 

 July. Chiefly distinguished from P. Sanguisorba by the larger fruit and 

 calyx. DISTRIB. Mid. and S. Europe. 



2. P. officina'le, Hook. f. ; flowers 2-sexual, stamens 4 not longer than 

 the calyx-lobes, fruiting calyx 4-wmged smooth between the wings. 

 H//ii!/i//'.mj'ba officinalis, L. Great Burnet. 



Damp meadows, from Roxburgh and Kirkcudbright southwards ; ascending to 

 l.fi(M) ft. in Yorkshire ; W. and N. of Ireland ; fl. June-Aug. Very similar 

 to P. Sanguitorba, but leaflets fewer, longer, less deeply serrate, usually 

 cordate at the base, and flower-heads often cylindric and \ in. long. 

 DISTRIB. Europe (Arctic), excl. Spain, Siberia, Dahuria, W. Asia. 



