236 UMBELLIFERAE 



Native. Paludal. Ditches, shallow slow streams, wet places. Common 

 and widely distributed, occurring in all the districts. P. June- 

 October. 

 First record. Slum nodijlorvm, Creeping water skerret, Dr. Noehden, 

 Mayor's Agr. Berks, 1809. 

 Apium nodiflorum is too frequent in the county to need localities 

 being given. The plant shows considerable variation. In shady 

 ditches it is often found with stems three feet in length and larger 

 leaves, having pinnae two inches long. When it grows in turfy soil 

 the whole plant may not cover more than a few inches of ground. 

 Two varieties are admitted into our floras, var. ocreatum, Bab. Man. 

 Brit. Bot. Ed. 8, 157 — Helosciadium nodiflorum, var. ochreatum, DC, 

 Prod. iv. 104 (,1830). H. repens, E. B. t. 1431, not of Koch, 1. c. 



1. Isis. Wytham. Appleton. Cumnor. Near Faringdon. 



2. Ock. Slum rei)ens. Between South Hinksey and the Abingdon 



Road, Baxter in Purt. Midi, Fl. iii. 25 (1821J. Cothill. Marcham. 

 Wantage. Frilford. 



3. Pang. Pangbourn. Near Moulsford. 



4. Kennet. Slum repens, Hampstead Park, Russell's Cat. Near Been- 



ham. Southcote. Aldermaston. Mortimer. 



5. Loddon. Foot of Winter Hill [^H. repens), Britt. Conir. Near 



Wargrave. Waltham. Bray. Old Windsor. Windsor Park. 

 Easthampstead. Loddon Bridge. Sonning. 



Var. REPENS, Hook. fil. Stud. FJ, 157 (1870). Sium repens, Linn, 

 f. Suppl. i. 8r. A. repens, Reich b. I.e., t. 1855. Helosciadium repens, 

 Koch, 1. c, 126. 



1. Isis. In the Wytham meadows. 



'1. Ock. In the Thames meadows near Oxford. 



5. Loddon. In a ditch at Early, Tufnail. (I have not seen this.) 



I am inclined to refer the plant, which is found on Port Meadow in 

 Oxfordshire and in other meadows on the Berkshire side of the 

 stream, to this variety. The involucre has from four to six bracts, 

 the peduncle is more than an inch long, being longer than the leaves. 

 In cultivation in garden loam the plant becomes much larger, the 

 leaves increasing to four inches, while the length of the peduncle 

 remains j)ractically the same, but the number of the involucels is 

 reduced to two or three and they become dimidiate. For cultivated 

 specimens I am indebted to my friend Mr. Rose. Probably this 

 creeping peduncled form has been evolved because the plant grows in 

 a situation which is from time to time submerged, and the peduncle 

 has been produced in order to lift the fruit above the water. In the 

 ordinary ditch form, which roots only at the lower nodes, the main 

 stem carries the sessile umbels above the water. The number of the 

 involucels, which Koch considers to be of considerable importance in 



