154 ACTINOMERIS SQUARROSA. SQUARROSE ACTINOMERIS. 



separation, the degree of individualization or consolidation ci 

 these original parts, result the different characters which arc 

 exhibited by the different parts of a plant. And we can see by 

 studying such plants as the one we are describing that not only 

 is this true of individual plants, but that differences between 

 species, genera, and orders depend on the same laws of individ- 

 ualization and cohesion, or on the varying degrees of rapidity 

 with which development takes place. An umbelliferous plant 

 is simply a Composite, with less tendency to an arrestation of its 

 axial growth, and a consequent union of parts. The seeds of 

 Composites often have so great a resemblance to the seeds of 

 umbelliferous plants that it is difficult to distinguish the order 

 by them alone. The seeds or " achenes " of the present species 

 greatly resemble those of the parsnip, and of similar umbelli- 

 fers, in the broad marginal wing on the edges, as seen in the 

 half-mature achene in Fig. 2, and its cross section Fig. 3, and 

 this resemblance is peculiarly conspicuous when the seed is 

 ripe. 



In old times Actiuovicris was thought to belong to Coreopsis, 

 and as a member of this genus the first species known to 

 Europeans is therefore described by Willdenow. Nuttall, 

 however, showed that it is much more nearly related to the 

 Hdianthus or Sunflower, although there are many points 

 of difference between the two, the one which will strike the 

 most casual observer being the small number of the ray-petals, 

 as already noted. The principal flower on our plate is repre- 

 sented with eleven rays, but this is unusual ; six, and often only 

 four, being found much more frequently. The name of the 

 genus, Actiuomcris, is based on this fact, aktin being Greek for 

 " ray," and uteris for " part," the compound thus signifying that 

 the flowers are only " partly rayed." 



We may sometimes notice a regular current of air moving in 

 the atmosphere with scarcely any apparent vibration of its wave, 

 while at other times the current is extremely fitful, — now calm 

 and flowing in one direction, now violent and coming in gusts 



