MISSISSIPPI EXPERIMENT STATION. 5 



The stnicture of the parents was also described and the hybrids com- 

 pared with them. 



The main conclusion reached from a study of these hybrids and a 

 number of others not named, was that the structure of hybrids is almost 

 exactly intermediate between that of the parents. 



"\A'underlich (1895) studied the structure of more than twenty 

 hybrids between different species of Cirsium. He found that in the 

 main the hybrids were intermediate between their parents anatomically ; 

 the hybrids showing in several cases an exact arithmetical mean between 

 the parents in the number of layers of cells in particular parts. The 

 h}'brid between Cirsium bulbosum and C. acaule showed for the most 

 part the anatomical characters of C. bulbosum showing a dominance 

 in anatomical characters. In instances in which the two parents 

 possessed different corresponding characters, as in the case of two 

 sorts of hairs, the hybrid produced both forms. 



Zschokke (1895) found that the anatomy of a hybrid between Carex 

 ampuUacea and C. vesicaria was intermediate between that of its parents. 



Parmentier (1897) described the structure of a number of Rosa 

 hybrids. They were intermediate in the main, but different ones 

 showed a leaning to one of the parents in certain characters. No very 

 striking conclusions were reached. 



Farmer (1897) reported that the hybrid fern Polypodium Schneidcri, 

 showed certain structural characters somewhat intermediate between 

 those of its parents, yet in the main, the characters were almost exactly 

 like characters found in one or the other of the two parents, blending 

 not being apparent. 



Paulesco (1900) compared the structure of hybrids and parent 

 plants in the genera Achillea, Senecio, Cirsium, Rosa, Dentaria, Sorbus, 

 Tilia, Viola, Primula, Rhododendron, Cistus, and Salix. He found that 

 the hybrids either resembled one parent closely or were intermediate. 

 In some cases certain organs resembled those of one parent, while other 

 parts were intermediate. Epidermal hairs were found to be interme- 

 diate in some cases, in others larger and more numerous than in either 

 parent; if the parents possessed two different sorts of hairs the hybrid 

 usually had both. 



Wilson (1900) discussed hybrids in the genera Passiflora, Ribes 

 and Begonia. This work dealt mainly with the external appearance of 

 the hybrids, Passiflora Buonapartea x P. caerulea, P. alba x P. Buona- 

 partea, Ribes nigrum x R. grossularia, and Tuberous Begonia x B. 

 coccinea. These hybrids were said to be intermediate in characters 

 examined. 



MacFarlane (1900) described the structure of a hybrid Drosera, 

 D. filiformis x D. intermedia. The structure of the hybrid showed a 

 minute blending of parental histological peculiarities in all parts; 

 leaves, axis of inflorescence, inflorescence, period of blooming, size and 

 color of blossoms, and floral structure, were all intermediate. Briquet 

 (1901) reported a combination of the histological characters of the 

 parents in Laportea hybrids. 



Gaijchery (1902) in comparing the tissues of Garrya elliptico- 

 Fadhenii with that of its parents G. elliptica and G. Fadyenii, found 



