18 ILUNOIS BIOLOGICAL MONOGRAPHS [108 



A number of variations from the normal type are found in this group. 

 While the flowers, with but few exceptions, are typically pentamerous 

 practically aU species show flowers with but two, three or four parts. Pis- 

 tils possessing three styles instead of two are rather common. In a number 

 of specimens the stamens were found to be petaloid with abortive thecae, 

 but in others the thecae were borne at the edge of the otherwise normal 

 corolla lobes with no indication of filaments. In one flower of C. pringlei 

 well developed scales were found on the exterior of the corolla ; normal scales 

 ako being present. A few flowers of C. ceratophora exhibited unmistakable 

 buds produced on the receptacle between the calyx and the corolla. Some 

 species predominatingly produce their flowers endogenously, e.g. C. glome- 

 rata, as reported by Bessey (1884), Goebel (1908), Stevens (1889), Thomp- 

 son (1899), etc. A number of other species have been seen in which 

 endogenously formed flowers were found to be more or less frequently 

 produced. In some specimens of C. cephdanthi practically all the flower 

 clusters are so formed. When formed internally the flower clusters usually 

 originate directly over haustorial areas and break forth in two more or 

 less parallel rows. 



Kuhn (1867) lists Cuscuta as one of a number of different "plantae 

 floribus cleistogamis." M tiller says (1883) of C. epithymum that it is 

 homogamous and "honey is secreted by the lower part of the ovary and is 

 sheltered by the scale-like appendages of the corolla. The flowers are 

 visited by Sphegidae and in the absence of insects fertilize themselves." 

 Knuth says (1899): "Die Staubfaden sind von Anfang an einwarts 

 gekrumt, sie neigen sich spater weiter nach innen, entweder bis zur Beriih- 

 rung mit der Narbe oder bis sie senkrecht uber derselben stehen, so dass 

 alsdann durch Pollenfall Bestaubung eintritt." and further: "Als Besucher 

 bemerkte H. Muller 2 Grabwespen: Crabo elongatulus, einzeln, PhUanthus 

 triangulum mehrfach; Kohl in Tirol die Faltenwespe PoHstes gallica." 



Extended observations of a number of patches of dodder failed to 

 reveal any insects alighting on the flowers. Mirande says (1900): "Le 

 Cuscuta fragrans qu'on trouve aux environs d'Anthenes repand unagreable 

 parfum de violettes; le C. reflexa de ITnde, possede una odeur de fleurs 

 d'oranger." A specimen of C. racemosa chiliana collected by Davis in 

 California was recorded as "fragrant." It is probable that the plants 

 exhibiting fragrance would be more liable to insect visits than those without 

 it. 



Cuscuta frequently is self parasitic, that is, often coiling about and 

 sending haustoria into its own stems. Saccardo records Dendryphium 

 macowanianum as parasitizing C. cassythoides and Peck records (1874) a 

 new species of Protomyces {P. tnartindalii) as occurring on C. gronovii. 

 A number of swollen stems and flower pedicels found during the course of 



