scopically pubcrulcnt dh niid-vcin ; lldwcr thyrsus blue, 6 in. long 

 and 2 in. broad: fruit round crested. .\o. .]2M [ypt in author's 

 Iirrliarium : cot\pcs in lierkeley and Smithsonian. 



In this Inbrid ( '. arborcits is the dominant factor in the 

 foliage and ( '. sf'iiiosiis in the fruit and flower. The leaf is in- 

 termediate in size, but in shape venation and serration, though 

 the latter is less marked, it is that of arboreus. The conspicu- 

 ous tomentum of the underside of the leaf in C. arboreus is but 

 faintly represented by the puberulency on the mid-vein. In 

 habit of growth it is more of a shrub than a tree. 



.\ few years ago Mr. Theodore Payne acquired some seeds 

 of C. arboreus from a garden in Santa Barbara. These when 

 sowed produce 50 per cent of C. arboreus, the others all similar 

 were of an unknown variety. These latter grew rapidly and 

 l)roduced blooms one of which is shown in the illustration. Mr. 

 Payne visited the source of the original seeds and found C. ar- 

 boreus and C. spinosus grouped together in one patch. No 

 other Ceanothus grew in the neighbourhood. He naturally and 

 I think correctly concluded that this unknown tree was a hybrid 

 between C. arboreus and C. spinosus. 



A number of these hybrids have been planted in the gardens 

 of Los Angeles as they promise to be one of the most orna- 

 mental and hardy of our native shrubs. It is more foliaceus 

 than C. spinosus and produces a larger flower than either of the 

 parent plants. 



C. spinosus has not been found in proximity to C. arboreus 

 in Catalina Island so they have not been subjected to the pos- 

 sibility of cross-fertilization in their native habitat. 



Some of the lilacs in cultivation have been produced by 

 cross-fertilization to which the wdiole genus readily responds. 

 On this account it has long been suspected that some at least of 

 our accepted species are really hybrids. C. vestitns Greene has 

 been considered a hybrid by some writers, but the evidence in 

 this district is against this supposition as our plants are found 

 in the desert regions far from any other species. C. soriedatus 

 is the only lilac in this district that looks like a hybrid. This 

 plant is rather rare here, and where it does occur the plants are 

 few and disseminated. Its appearance suggests a cross be- 

 tween C. divaricatns and C. oliganthus. Cultural experiments 

 alone will determine the status of our doubtful species. 



AnstruthEr Davidson, C. M., M. D. 



46 



