240 The Flora of Wiltshire. 



notes, and seldom to be found for any length of time in the same 

 places. A singular wiry and slender plant, with much the habit of 

 " Bupleurum tenuissimum," and remarkable for the very small few- 

 rayed umbels. Entire -plant extremely smooth and glabrous, dull 

 glaucous green, very weakly aromatic. 



P. sativum (Hoffm.) Engl. Bat. Suppl. f. 2793. Common 

 Garden Parsley, distinguished from this by the doubly pinnated 

 root-leaves and the many rayed umbels, has no claim to a place in 

 a County Flora, nor have I ever seen it even apparently wild. 



Helosciadium, (Koch.) Marsh-wort. 

 Linn. CI. v. Ord. ii. 

 Name. Compounded of helos, a marsh, and sciadion an umbel, 

 meaning an umbelliferous plant, inhabiting marshes. 



1. H. nodijlorum, (Koch.) knot-flowered Marsh-wort. Sium (Sm.) 

 Engl. Bat. t. 639. Reich. Icones, t. QQ. 



Locality. Banks of the Avon, ditches, and slow running streams. 

 A frequent companion of the water-cress. P. Fl. August. Area, 

 1. 2. 3. 4. 5. Distributed throughout all the Districts. It varies 

 much in size and foliage, when the plant is small, with several 

 slender quite prostrate creeping stems, deeply toothed leaves, and 

 stalked umbels, it is the H. repens, (Koch.) Sium-repens, (Linn.) 

 Engl. Bot. t. 1431, and is not uncommon in the county, growing 

 in watery places and boggy meadows, and on the borders but not 

 in the water of ditches and rivulets. 



2. H. inundatum, (Koch.) inundated Marsh-wort. Sium (Smith) 

 Engl. Bot. t. 227. 



Locality. Floating in swamps and shallow ponds, or creeping 

 on their partially exsiccated margins, rare. P. Fl. June, July. 

 Area, 1. 2. 3. 4. 5. /« all the Districts but easily overlooked, and 

 consequently supposed to be more rare than is the fact. 



SisoN, (Linn.) Stone or Hone-wort. 

 LiNjf. CI. V. Ord. ii. 

 Name. From si&im, signifying in Celtic a rimning brook ; some of 

 the plants formerly placed in this genus delighting in such situa- 

 tions. 



