TJMBELLIFER^. 117 



reimtation of removing freckles. It is said also to dissolve mucus, and on this 

 account is used as a gargle in some cases of throat affection. In Germany it is 

 prescribed in asthma and dropsy. A species of coccus infests the root, from which 

 colouring matter may be procured. 



GENUS XV— ^ I U M. Linn. 



Calyx-limb of 5 teeth, sometimes very small. Petals roundisli- 

 obovate, emarginate, with an inflexed lobe from the notch. Cremo- 

 carp roundish-ovoid or sub-globular, laterally compressed ; colu- 

 mella 2-partite, the branches generally adhering to the mericarps ; 

 mericarps with 5 equal filiform ridges ; interstices each with 2 to 5 

 vittse. Involucre variable. 



Herbs, generally growing in wet places, with pinnate leaves 

 and serrate or cleft leaflets. Umbels many-rayed ; flowers white. 



We are told that the name of this genus of plants owes its origin to the Celtic 

 word sire, water, in allusion to the favourite habitat of most of the species, or perhaps 

 it may come from (reiM (se'io), I shake, as agitated by the stream in which it gi'ows. 



Section I.— EU-SIUM (Sium, Koch). 



Cremocarp not didymous, the lateral ridges marginal ; vittse 

 superficial ; stylopod depressed. 



SPECIES I.— SIUM LATIFOLIUM. Linn. 



Plate DLXXXYII. 



Reich. Ic. n. Germ, et Ilelv. Yol. XXI. Tab. 1877. 

 Billot, Fl. Gall, et Germ. Exsicc. No. 2846. 



Stem erect, very thick, deeply furrowed, slightly branched at 

 the top. Leaves pinnate ; pinnae oblong-lanceolate, evenly serrate 

 or serrulate, in the submerged leaves sometimes pinnatifid. 

 Umbels mostly terminal, on stalks longer than the rays. Invo- 

 lucre of numerous entire or remotely-serrate leaves ; involucels 

 of numerous subscarious acuminate leaves. Cremocarp longer 

 than broad, roundish-oval-ovoid, with prominent ridges. 



In ditches and still places by the edge of rivers. Rare, but 

 widely distributed in England ; rather common in the fens of the 

 Eastern counties. In Scotland very rare : the only specimens I 

 have seen are from the neighbourhood of Ealkirk, Stirlingshire. 



England, Scotland, Ireland. Perennial. Summer. 

 Eootstock shortly creeping, stoloniferous, with numerous long 



