[LLOYD] ORIGINATION OF ASCIDIA 77 



organs. It is readily conceivable that such circumstances set up 

 internal conditions in the growing organs within the bud which may 

 be called mechanical/ a more exuberant growth within and below, 

 opposed by already indurated or at best slowly growing outer regions 

 and parts. The frequency of ascidia and concurrent forms-changes 

 (fasciations) in cabbages, spinach and the like, of which a plenitude 

 of instances have been cited' strengthens the relevance of this view. 



One of the most significant facts observable in the cotton plant is 

 the tendency to form ascidia in a longitudinal series. In the case 

 shown in figure 3 there was an attempt to form an ascidium near the 

 base of the leaf the notching passing between the internal and external 

 lobes on both sides, and in each lobe. In the case of figure 15, a 

 second transverse notching and folding of tissue occurred within a 

 perfect ascidium. These cases, among others, seem to point to 

 transverse pressure against the moieties of the laminae mutually 

 apposed in vernation. Both G. H. ShulF and myself have observed 

 a precisely similar condition in Fraxinus.^ Indeed every detail of 

 behaviour in Fraxinus I find duplicated in Gossypimn. 



It is also noteworthy that mutual effects of the apposed moieties 

 of the leaf as a w^hole and of the lobes taken singly are evident. Simpler 

 expressions of this were briefly described by me some time ago.^ 

 It occurs also in the parts of flowers, especially petals, and in doubled 

 flowers it is quite frequent (e.g. Tulipa). Quite recently Miss Lutz 

 has found that the same efïect in the notching of petals whose edges 

 mutually interfere occurs in the Oenotheras, especially in 0. hipartita 

 (in 35 percent of all the flowers) and less frequently later than earlier 

 in the season.^ This behaviour, which characterizes this mutant, 

 results from a reversal of aestivation which may or may not produce 

 the final effect of notching, and the seasonal frequencies indicate the 

 effects of changed rates as well as directions of growih. 



^Fasciations may be caused by pruning, lateral pressure on the growing parts 

 induced by binding. (Sorauer, Hand b. , der Pflanzenkrankheiten Vol. 1, p. 334) 

 and by injury (Knox, A. A. Plant World 10:145, 1907). See also Worsdell, I.e. 

 Hus {I.e.) cites the fact of the common occurrences of fasciation on the earliest 

 shoots of cultivated asparagus. 



-See Worsdell, I.e.; Gager, C. S. Teratological Notes. Torreya. 8:132-137. 

 Je. 1908. 



^Science n.s. 23:201, 1906. 



■'In tree no. 10456 (4) grown at Carmel, Cal. (experimental garden, Coastal 

 Laboratory, Carnegie Institution of Washington), and in tree no. 10456 (109) in 

 the grounds of McGill University. 



^Mutual Irregularities in Opposite Leaves. Torreya 2:137-139. Aug. 1902. 



^Lutz, A. M. Fifteen— and Sixteen— chromosome Oenothera Mutants. Am. 

 Jour. Bot. 4:53-111. Feb. 1917. 



