DEPARTMENT OF BOTANICAL RESEARCH. 



73 



- chal. 



of insect work, which, if it had obtained at all, must have been effective 

 on the unopened flower-bud, or even the growing apex. Again, galls 

 are produced in both normal and abnormal ovaries, or may be absent 

 from both, though it should be added that the absence of a gall does 

 not preclude entirely the presence of wound response, which may or 

 may not have been caused by the insects, either or both. 



The morphological departures from the normal, aside from the 

 formation of galls, include antholyses in various expressions, among 

 which may be mentioned separate pistils, conjoined and open pistils, 

 the occurrence of a gynophore, flowers superimposed in series, phyllody 

 of stamens and replacement of ovules by shoots in the axils of the 

 carpel, together with intergradations 

 between those and perfect ovules. A 

 study of the series supports the view 

 that the ovule in Phytolacca is the 

 homologue of a shoot, of which the 

 first leaf is decurrent and constitutes 

 the outer integument. The inner 

 integument is apparently compound 

 of two or more connate leaves, while 

 the nucellus is the vegetative apex, 

 normally of the chief axis but terato- 

 logically sometimes of a branch. The 

 embryo-sac may be entirely absent 

 or may be present. The megaspore 

 has been observed in both chief and 

 secondary growing-points of shoot- 

 like ovules. This interpretation in 

 its general form is not a new one, 

 but the material is of such variety 

 morphologically as to make it possible 

 to throw new light on the origin of 

 the integuments. (Fig. 2.) 



The galls show a flesh}^ hypertrophy of the pericarp and of the ovules, 

 which, when fundamentally normal in form, may display enlargement 

 of parts and inflation of the integuments. Though different insects 

 have been found in adjacent carpels, no difference in structure of the 

 galls was visible. The innermost hypertrophied tissue, together with 

 the ovules, constitute the food of the larvae. 



o. int. 



Fig. 2. — Vegetative shoot replacing an 

 ovule in Phytolacca (Tucson, No. 1). 

 The parts of the normal ovule corre- 

 spond to the parts indicated as follows: 

 o. int., i. int., outer and inner integ- 

 ument; chal., chalaza; fun., funicle; 

 raphe. The margin of the outer integ- 

 ument is indicated by a broken line. 



The Deterviinative Action of E7ivironic Factors upon Neobeckia aquatica 

 Greene, by D. T. MacDougal. 



Neobeckia is a water-cress inhabiting the marginal strand of lakes in 

 eastern America below high water-level, which displays a range of leaf 

 forms from oblong-lanceolate, nearly entire blades, to others finely 



