148 CALIFORNIA. [Composite*. 



basi cuneatis apice grosse dentatis, capitulis terminalibus solitariis vel subtribus in spicas 

 glomeruliformes axillares digestis, involucri foliolis glabris apice fimbriatis, achenio oblono-o 

 glaberrimo pluri-costato. — Mich. — Pursh, Fl. Bor. Am. v. 2. p. 523. 



There are two very distinct states of this plant, which we had almost supposed to be different species ; 

 but Lessing, whose authority is doubtless high, as he appears to hare seen numerous specimens, 

 describes both without distinguishing them even as varieties. In one, the heads of flowers are collected 

 usually by threes, into short compact spikes or racemes, which are almost invariably axillary. In the other, 

 the inflorescence is more lax, and the heads of flowers are constantly solitary and terminal. Neither in the 

 involucre, achenium, pappus, nor leaves, is there any difference. It was found also by Mr. Menzies, on the 

 coast of California. 



1. Xanthium Canadense. Mill. — X. maculatum. Ilqf. in Sill. Journ. — X. orientale. 

 Linn.Jil. 



The fruit of this species is larger than that of X. strumarium, and the two beaks to it are slightly incurved 

 at the apex, while in A', strumarium they are nearly straight. Whether these be sufficiently good characters, 

 we are inclined to doubt, but have not been able to discover any others. We presume it is the X. stru- 

 marium of Pursh, Nuttall, Elliott, and other North- American Botanists, and indeed we have seen no other 

 from North America. 



1. Ambrosia artemisiafolia ; caule birsuto, foliis bipinnatifidis subtus canescentibus laciniis 

 sinuato-dentatis obtusiusculis, racemis terminalibus ternis aggregatis. Linn. — Pursh, Fl. 

 Bor. Am. v. 2. p. 581. — A. absinthiifolia. Mich. Am. v. 2. p. 283. 



The spines of the fruit are short and strong. 



1. Franseria Chamissonis ; hirsuto-incana, caule decumbente herbaceo, foliis confertis 

 rotundato-ellipticis integris bipinnatisectisve segmentis divergentibus obtusis, petiolis planis, 

 capitulis masculis cernuis fcemineis erectis. — Lessing in Linnaa, v. 6. p. 507. 



The solitary and most imperfect specimen of this plant in the Collection, we have compared with one re- 

 ceived from Chamisso. The leaves seem very variable. 



1. Bidens chrysanthemoides ; foliis lanceolatis elongatis acuminatis connatis remote serratis 

 glabris, floribus longe radiatis cernuis, involucri foliolis exterioribus foliaceis interioribus 

 longioribus. — Mich. Am. v. 2. p. 136. 



1. Tridax? galardioides ; hispido-pilosus, foliis alternis sessilibus lineari-lanceolatis 

 inferioribus pinnatifidis. 



Caulis herbaceus, decumbens, patentim hispido-pilosus, ramosus ; rami subelongati, usque ad apicem parce 

 foliosi, capitulum unicum terminalem gerentes. Folia lineari-lanceolata, alterna; inferiora pinnatifida, seg- 

 mentis brevibus, obtusis, patentibus, superiora integra omnia hispide pilosa. Involucrum hemisphiericum, 

 simplex, polyphyllum : foliola oblonga, acuta, basin florum radii eorumque achenia involventia. Corolla 

 radii lutea?, basi attenuatie, apice explanatse, plana;, trifidse, stylum absque staminibus gerentes: disci 

 tubulosae, lutea?. Pales lineari-oblongse, submembranace.-e, pluriseriales, inter radii discique flores interjects;, 

 receptaculo piano alioquin nudo. Anthers purpurascentes, ecaudate, Styli rami recurvati, appendicitis 

 linearibus puberulis superati. Achenia (juniora) oblonga, erostrata, basi attenuata; radii glabra, apice calva; 

 disci pilosa; pappo persistente rigido basi plumoso apice simplici. 



If this were to form a new genus, we would propose the name of Layia, after one of the discoverers; 

 and this Mould principally differ from Tridax or Balbisia, by the shape of the involucre, its consisting of 

 numerous leaves, which are opposite to, and are respectively wrapt round, the achenia and tube of the corolla 



