DICOTYLEDONS 



215 



The third order of the Anisocarpse, the Contortse, 

 includes several characteristic families, among them 

 the milkweeds (Asclepiadacese) and dogbanes (Apo- 

 cj'naceee). To the latter belong the oleander and 

 periwinkle, while the gentians, and the olive family 



Fig. 53 (Sympetalse, Labiatiflorse, Compositse) . — A, flower of dead-nettle 

 (Lamium), the flower strongly zygomorphio; B, stamens and pistil of 

 Lamium; C, flower of speedwell (Veronica), the stamens reduced to 

 two; D, flower of toad-flax (Linaria), the flower zygomorphic, and 

 the base of the corolla prolonged into a spur ; E, inflorescence of the 

 Canada thistle (Cirsium), the small flowers aggregated into a head 

 which looks like a single flower ; F, an individual flower of E ; o, the 

 inferior ovary; p, the hairs which form the "pappus," or calyx; ah, 

 the coherent anthers ; G, inflorescence of the may-weed (Maruta), the 

 outer flowers sterile and petal-like, serving merely as organs for attract- 

 ing insects ; H, one of the tubular perfect flowers from the central part, 

 or disk, of the inflorescence of Maruta ; I, a single flower from the inflo- 

 rescence of the dandelion : all the flowers are alike and have the corolla 

 split open and strap-shaped ; p, the feathery pappus ; o, the ovary. 



(Oleacese), with the lilac and ash as familiar representa- 

 tives, also belong to the Contortse. 



The highest of all the Anisocarpae, and therefore at 

 the head of the whole vegetable kingdom, are the 

 Aggregatse, including several families. Of the lower 

 families, the honeysuckles (Caprifoliacese) and the 

 madder family (Rubiacese) are the best known, while 



