Anderson and Schafer. — Species Hybrids in Aquilegia. 641 



There are good reasons for believing that this represents the ancestral con- 

 dition of the genus rather than a ' reduction '. In the first place it is 

 similar to the honey glands at the bases of the petals in many of the related 

 genera of the Ranunculaceae. In the second place, A. ecalcarata differs 

 from the remaining species of the genus in several other characters, such as 

 the shape of its fruit, the colour of its flowers, and its general aspect. In all 

 of these characters it reminds one of certain genera closely related to 

 Aquilegia, such as Isopyruni or Anemone. Drummond and Hutchinson (3) 

 even transferred it to Makino's genus Seini- aquilegia, concerning which they 

 wrote : ' Semi-aquilegia, with saccate petals, the only remaining link showing 

 the origin of the remarkable genus Aquilegia, which as evidenced by the 

 great variability of its species and its wide range, is probably still in a state 

 of flux.' 



Be that as it may,^ we undoubtedly do possess in the spur oi Aquilegia 

 a series of forms showing various degrees of similarity, which might easily 

 be arranged in a phylogenetic sequence. But in Aquilegia such a specula- 

 tive arrangement can be treated experimentally, for the various members 

 of the series are interfertile and can be crossed one with another. Not only 

 that, but in ecalcarata we even possess ' a living fossil ', similar to the 

 ancestral type in many respects, yet capable of producing fertile hybrids 

 with its more highly elaborated sister species. 



Cytologically, Aquilegia'is not very favourable material. The chromo- 

 somes are very small ; the pollen mother-cells are not easy to fix. The fol- 

 lowing numbers have previously been reported : 



A. atropurpurea 



A. chrysantha . 



A. haylodgensis , Hort. 



A. vulgaris 



A. vulgaris parviflora 



A. vulgaris x chrysantha 



n. in. Reported by 



14 Langlet 



7 Scalinska 



14 Langlet 



7 Winge 



14 Langlet 



7 Skalinska 



The following root-tip counts were made : 



A.flabellata, Hort 14 



A. chrysantha, Gray (New Mexico) 16 



A. chrysantha. Gray (Arizona) . . 16 



A. vulgaris, var. ' China Blue ' . 16* 



The chromosome numbers reported above indicate no gross chromo- 



' See, for instance, Ulbrich (8). 



' The flabellata was of commercial origin. The specimens of chrysantha were grown from 

 seed from wild stands. 'China Blue ' is the laboratory name of a variety wnich turned up among 

 the stocks originally got together at the John Innes Institution from various sources and hpnded 

 over to the junior author in 1937. Its origin is unknown to us ; it clearly belongs to A .vulgaris, 

 L. and it breeds true.. It is slow growing, about half the height of typical vulgaris but wiih flowers 

 of the same size. The flowers are of a light-blue colour and tinged red in the bud. This very 

 distinct variety has clearly originated from type vulgaris by some form of cytological aberration. 



