UMBELLIFERJE. 103 



lower leaves with the segments of the leaflets mostly linear or 

 strapshaped, not setaceous ; the involucel of 5 or 6 leaves. 



Least Water-Parsnip. 



GENUS VIII— PET ROSE LINUM. Hoffm. 



Calyx -teeth obsolete. Petals sub - orbicular, nearly entire, 

 slightly notched, with a small inflexed point. Cremocarp oval- 

 ovoid or sub-globular, laterally compressed, subdidymous ; colu- 

 mella free, bipartite, or cleft at the top ; mericarps with 5 filiform 

 ridges ; interstices each with a single vitta attenuated at each end. 



Herbs differing much in aspect, with yellowish or greenish-white 

 flowers. 



The name of this genus is derived from the Greek words Trtrpos (petros), a rock, and 

 oikivov (selinon), parsley, in reference to the habiiat of the species. 



SPECIES I.— PET ROSE LIN UM SATIVUM. Hoffm. 



Plate DLXXVI. 



Eeich. Ic. FL Germ, et Helv. Vol. XXI. Tab. 1856. 



Billot, FL Gall, et Germ. No. 2793. 



P. hortense, Hofm. Eeich. Ic. FL Germ, et Helv. Vol. XXI. p. 10. 



Apium Petroselinuni, Linn. Sp. Plant, p. 379. 



Stem erect, stout, furrowed, slightly flexuous. Lower leaves 

 triangular in outline, ternately bipinnate ; leaflets broad, 3-cleft 

 or 3-partite, cut, and serrated ; lower stem-leaves shortly stalked, 

 similar to the radical ones, but smaller ; upper ones pinnate, 

 with wedgeshaped or elliptical-strapshaped segments. Involucre 

 dimidiate, of 2 or 3 leaves, one of them often pinnatifid ; involucel 

 of numerous lanceolate leaves. Umbels flat-topped, with the outer 

 rays all equal, spreading-ascending. Columella split to the base. 

 Styles reflexed, longer than the stylopod. 



On rocks, old buildings, and waste places. Not unfrequent, 

 but no doubt escaped from cultivation. 



England, Scotland, Ireland. Biennial. Summer. 



Boot fusiform, producing the first year a number of ascending 

 leaves on stalks 2 to 9 inches long ; lamina 3 to 6 inches, or more, 

 with the lower pair of pinnae on long stalks, and more remote from 

 the succeeding 1 pair than that from the next ; leaflets f to 1 inch long, 

 rhomboidal-ovate, cleft, with the segments wedgeshaped and cut 

 into lobes or teeth with rounded edges. Flowering-stem produced 

 the second year, 1 to 2 feet high, solid, angular, much branched, 



