SPECIES AND VARIETIES. 243 



terminal peduncles, of 36 rays, bearing numerous small white 

 flowers on short pedicels ; fruits very small. Marshy places 

 near the sea. Fl. June to August. The Celery of our gardens 

 is a cultivated variety, with enlarged leafstalks. 



(Ill) Helosciadium. 



H. nodiflorum : stems procumbent, rooting, the flowering 

 ones ascending or nearly erect, 12 feet high, glabrous ; leaves 

 pinnate, with 3-10 or more pairs of ovate-lanceolate toothed 

 segments ; umbels nearly sessile, either opposite to the leaves 

 or between the upper branches, with 56 (rarely 8 or 4) rays ; 

 general involucre usually wanting ; partial involucre of several 

 small, lanceolate bracts. Marshy meadows and ditches. Fl. 

 July, August. It varies much in size and foliage. 



H. repens is a smaller, much branched, more creeping form, 

 with 3-5 small broad leaf-segments, and longer peduncles to 

 the umbels, occasioned by growing in drier situations. 



H. inundatum : stems glabrous, creeping and rooting at 

 the base like H. nodiflorum, but smaller, and more slender, 

 often partly immersed in water, the submerged leaves divided 

 into capillary segments; flowering stems 6-8 inches high, 

 with small ternate or pinnate leaves, the segments three- 

 toothed or three-lobed, each lobe often again three-toothed; 

 umbels on short peduncles opposite the leaves, generally of 

 2-3 rays without involucre, the partial umbels of 5-6 small 

 flowers, with 2-3 minute bracts. Swamps and shallow pools. 

 Fl. June, July. 



(112) Sison. 



S. Amomum: annual or biennial; stems erect, glabrous, 

 two feet high or more, with many stiff, slender branches; 



R 2 



