Studies of Teratological Phenomena. 85 



fasciation, will be described in detail, beginning mth the grosser structures 

 such as stem and inflorescence, and concluding with a description of 

 the changes brought about in the reproductive organs. Special care 

 will be observed in the description of the leaves and floral parts 

 because of the variability in number produced by the presence of this 

 character. 



Seedlings. Generally normal; tricotyls rare. 



Stem. Cylindrical base, gradually developing the characteristic flat, 

 ribbon -shaped, fasciated condition. Grooved or ribbed by fine vascular 

 strands. Linear width, 1'25 — 5 "5 cm. Some stems more flattened than 

 others. Fasciated part of stem not the same throughout its whole 

 extent. Variable, often slightly curved owing to irregularities of growth. 

 Usually unbranched except for the cluster of small twigs constituting 

 the inflorescence. Pith an ellipse in cross section. Anatomical pre- 

 parations give no support to the "concrescence" theory. 



Leaves. Phyllotaxy very irregular. Double leaves and leaves 

 with broadened apices not uncommon. Great increase in number as 

 compared with normal parent race. Many normal-sized leaves and many 

 smaller than normal (402). Variation in number of leaves correlated 

 with size and character of main axis. Variation in number per plant 

 ranges between 28 — 152 as taken from records of over 200 plants 

 grown under five different environments and during five seasons. Normal 

 as regards form. (See Table 2.) 



Inflorescence. Bifurcate, multiradiate, rarely "annular" or 

 funnel-shaped, often single main axis, abruptly terminated by a number 

 of small twigs. Flower -bearing twigs small, densely clustered into 

 '"witch-broom'-like bunches or irregularly distributed along the sides and 

 apex of the stem. 



The floral structures were deformed in a large number of ways, 

 the most prominent being the increase in number of parts to each whorl 

 per flower. This numerical increase is not of a constant nature, in the 

 sense of a variation from one definite number to another, a statement 

 also true of the change in phyllotaxy and leaf number. Nor does it 

 at all substantiate de Vries' notion of a duplication in number such 

 as is said to occur in Geranium moUe fasciatum. In a figurative way, 

 one may compare the variability of Nicotiana tabaciim fasciata to that 

 of an arc made by a pendulum, provided there was a force behind the 

 device to change the rate of its swing and the size of its arc when 

 affected by things external to itself. Tables 3 and 4 give a better idea 



