208 GENETICS [Bot. Absts. 



1467. Terry, E. I. A formula method for estimating timber. Jour. Forestry 17: 413- 

 421. 1 fig. 1919. — A formula is worked out to determine the volume in board feet by using 

 the breast-high diameter, the merchantable length, the merchantable form factor and the 

 ratio of beard feet to cubic feet. Using the derived formula, a constant is determined for 

 each diameter class which will give the board-foot volume of a tree when multiplied by the 

 length of the tree. Plotting these values and smoothing off the curve, a volume table can 

 readily be constructed. [See also Bot. Absts. 3, Entry 1465.] — E. N. Munns. 



1468. Totjmet, J. W. Need for a unified forest research program. Jour. Forestry 17: 

 281-289. 1919. — Research in forest problems in the United States has been left largely to 

 the Forest Service which is primarily an administrative organization. A unification and co- 

 ordination of forest research in the various educational centers is needed and an experiment 

 station should be established, with government aid, in each state. — E. N. Munns. 



1469. Wirt, G. H. Pennsylvania's opinion. Amer. Forestry 25: 1283-1284. 1919.— (A 

 contribution to the general topic "A national forest policy.") The writer believes that the 

 most essential factor in the national program must be educational work. Other suggestions 

 are made as to secondary provisions. — Chas. H. Otis. 



GENETICS 



George H. Shull, Editor 



1470. Anonymous. Inheritance studies with poultry at the Rhode Island Experiment 

 Station. Rhode Island State College Bull. 13: 41-42. 1918.— Part of the Director's Annual 

 Report, covering progress of the work under way. — H. D. Goodale. 



1471. Coe, H. S. Origin of the Georgia and Alabama varieties of velvet bean. Jour. Amer. 

 Soc. Agron. 10: 175-179. 2 fig. 1918. — The Florida velvet bean (Stizolobium Deeringianum) 

 requires a frost-free season of 8-9 months. In 1906 some early-maturing velvet beans were 

 found in Summer, Georgia, growing from seeds which had been raised there. The plants were 

 small, and ripened their first pods three months or more after sowing. They gave constant 

 early progeny. In 1908 a similar mutant was observed at Broxton, Georgia; this time from 

 Florida-grown seed. A different mutant was found at Flomaton, Alabama. In 1911 one 

 plant in a field of Florida-grown seeds was seen to flower and mature earlier. Its progeny 

 were constant, ripening in six months or less, and were larger than the Georgia mutant. In 

 consequence of the discovery of these early varieties, the area under velvet beans has increased, 

 in the past three years, from less than one million, to more than three million acres. — John 

 Belling. 



1472. Collins, G. N. Structure of the maize ear as indicated in Zea-Euchlaena hybrids. 

 Jour. Agric. Res. 17: 127-135. PI. 16-18, 1 fig. June 16, 1919.— Second and subsequent 

 generations of Zea-Euchlaena hybrids grade back to the parental types and form a complete 

 series of intermediates. In analysing the hybrids it was found necessary to consider as a 

 morphological unit the association represented by a paired sessile and pedicelled spikelet 

 as they occur in the staminate inflorescence. This unit has been designated "alicole." — With 

 respect to the pistillate inflorescence all stages are found between the simple spike of Eu- 

 chlaena and the many-rowed ear of maize. In none of these intermediates is there found any- 

 thing which could serve as support for either the fasciation or "reduced branch" methods of 

 forming a many-rowed spike but on the contrary a third method is clearly indicated. This 

 is by a shortening and twisting of the rachis of a single spike of Euchlaena accompanied by 

 an increase in the number of alicolcs. Further support for this method is found on ears of 

 pure maize which reduce the number of rows in passing from the base to the tip. In these 

 cases the loss is almost invariably two rows and both are lost at the same distance from the 

 butt of the ear, leaving no region with an odd number of rows. Although two rows are dropped 

 at once they are not adjacent but are nearly on opposite sides of the ear. This is what should 



