THE MORPHOLOGY OF WEEDS 



125 



Fig. 60. Inflor- 

 branched escence. Spike of 



the deter- cat - ta . iL 

 geon.) 



The milkweed and carrot have umbels. The spike is like 

 a raceme with a lengthened axis, the flowers being- sessile, 

 like those of the plantain. A head is a 

 roundish cluster of flowers which are ses- 

 sile, as in the clover and buttonball. The 

 spadix is a fleshy spike, as in the Indian 

 turnip, the spathe being the leaf over the 

 spadix; the flowers of the spadix are im- 

 perfect. The catkin is a type of inflores- 

 cence found in the willow and hickory. 

 The panicle is a compound flower cluster 

 found in many grasses ; that is to say, it is 

 like a raceme, but the 

 stalks are 

 again. Of 



minate inflorescence the 

 most important is the cyme. The cyme 

 is a flat topped or convex flower clus- 

 ter somewhat like the corymb, but 

 with the terminal flower developing 

 first. A glomerule is a cyme very much 

 compacted, resembling a head. 



Flowers are perfect or hermaphrodite 

 when provided with the essential or- 

 gans, stamens 



and pistils ; complete when they 

 have all the floral envelopes, 

 calyx, corolla, and stamens and 

 pistils; regular when all the 

 parts of each set are of the same 

 shape and size, like the rose; 

 irregular when some of the dif- 

 ferent floral circles are dissimilar 

 or unequal, as in the clover, wood 



sage, and mint ; monoecious when Fi - 6z - Inflorescence 

 u .< j ,.,i - Raceme of barberry. (C. M. 



both staminate and pistillate King.) 



Fig. 61. Inflo- 

 rescence. Head of 

 ragweed, achene 

 above. (C.M.King.) 



