12^ 



nothing ()f its lutmally llaltoiied cjiiix-ls. yt^lluw lluwcrs. ami gt-noial luiltit. 

 ft sct'ni>3 to LM>inci(le ill cliaracteis iiiuist with \'rl<rti, Iml i.s at vaiiaiic*' in 

 the most inipoitant cliaractcr in that gi.'iius, viz: a strongly involute .st'fd. 

 I'lU'losing a eeiitiai cavity. Ahiiost ichMitical in habit with .\[imf ninnt. its 

 t-aipels aro llattenc I laterally instead of dorsally, the seed-face is not so 

 l>rondly but more deeply concave, the intermediate ribs dike TV/rrn) are 

 much nearer the dorsal tlian the laterals, instead of iieing eipiidistant, its 

 oil-tubes arc more nniforin in size, and its calyx-teeth are obsolete. It also 

 simulates Alchx iicunHx in general api)earance, but differs radically in 

 fruit structure. Such a combination of resemblances and differences can 

 best be expressed by an indepeiident genus, and hence we us(» Grays 

 section name under Tini>«-lii(t and raise it to generic rank. 



1. M. Texana. Acaulesccnt: scape 2 to H inches high, 

 longer than th(; lca\ es, somewhat scahrous at base of umbels: 

 leaves 5 to 7-pinnate; lower pinna- petiohilate, pinnatch' parted ; 

 segments cuneiform, 8 to r)-clcft: umbel ~) to S-rayed: fruit ^ ^j 

 lines long. (Fig. 141.) -'/'ausrliia Tcxaiia (»rav, PI. Liiulh. ii. 

 211. Eulofhns Tesaiiiis IJenth. .K: Hook. (Jen. Plant, i. SHri. 

 Western Texas, and extending iiito Mexico. Fl. .Tuly. 



44. CONIUM Linn. Gen. n. 830, — Poisonous biennials, 

 with spotted stems, large decompond leaves with lanceolate pin- 

 natilid leaflets, involucre and imolucels of narrow bracts, and 

 white flowers. 



C. MAcLLA'iiM L. A large branching l^uropean herb, in 

 waste places throughout the northeastern states and Canada; also 

 found in California. Fl. July. (Fig. 142.) 



45. SIUM Linn. Gen. n. 848. — Smooth perennials growing 

 in water or wet places, with pinnate leaves and serrate or pinnatifid 

 leaflets, involucre and involuccls of numerous narrow bracts, and 

 white flowers. 



Bonthani & Hooker refer our two species of .S'/»m to Apiittn; but they 

 seem abundantly distinct, as indicated by Watson, Bot. Calif, i. 261. The 

 oil-tubes are never solitary in all the intervals, and the prominent grou|i 

 of strengthening cells in the outer edge of each rib, as well as the broad 

 intervals, still further emphasizes the distinction. There is no better de- 

 fined generic group than that formed by our two species of Sium, being so 

 nearly identical in fruit and so easily separated from all other genera. 



1. S. cicutaefolium Gmclin. Syst. ii. 482. Stout, 2 to (S 

 feet high: leaflets 3 t(j 8 pairs, linear to lanceolate, sharply serrate 



