November 18, 1893.] 



SCIENCE. 



695 



down ; when the new stems rising from the 

 same root-stocks the next year are often 

 shorter, weaker, scantier and paler in inflo- 

 rescence and less varied in leaf. 



N^ Resting stage, when, instead of the 

 preceding (iV°) or after it, the root-stock 

 develops radical leaves only for a series of 

 years. 



N'' Siirculns stage, a lateral offshoot, aris- 

 ing from the preceding root-stock, rising 

 and making readj' to enter npon the radical- 

 tuft stage, iV"'^, and renew the round of the 

 life-historj'. 



Specific distinctions are hardly to be 

 found in the constant absence or pi-esence 

 of any of the less usual stages, but rather 

 in the relation the plant bears to them when 

 they are found, the ease with which they 

 are induced or thrown off, and the shapes 

 assumed when induced. Some species habit- 

 ually elide one or more terms in the series, 

 some accelerate them, some prolong or ac- 

 centuate them. An exceptional develop- 

 ment does not invalidate a specific charac- 

 ter, as its possibility is latent in all. 



The Embryology of Taxus. E. J. Dueand. 



In this paper the development of the 

 female prothallium is traced from one of an 

 initial axial row of about three cells. The nu- 

 clei which result from the division of the nu- 

 cleus of the macrospore arrange themselves 

 in a peripheral layer, and walls are formed 

 between them so that the young prothal- 

 lium is in the form of a hollow sphere, the 

 center of which gradually becomes solid 

 from the ingrowth of the cells. The arche- 

 gonia are developed at the distal end of the 

 prothallium. The neck of the archegonium 

 consists of four cells, instead of one, as is 

 usually stated for this plant. 



Effect of Fertilizers on the Germination of Seeds. 



Gilbert H. Hicks. 



The tests were made with the seeds of 

 wheat, lettuce, radish and crimson clover. 

 The conclusions reached are as follows : 



1. One per cent, strengths of muriate of 

 potash and of sodium nitrate are very detri- 

 mental to seeds, whether applied directly or 

 mixed with the soil. 



2. Fertilizers composed of phosphoric 

 acid or of lime are much less injurious to 

 germination, and if not used in excess may 

 be harmless. 



3. Commercial fertilizers should not be 

 brought into direct contact with germina- 

 ting seeds. 



4. The effeot of treating seeds with 

 chemicals before planting is no index to the 

 action of those chemicals when applied as 

 manures to the soil. 



5. The chief injury from chemical fertil- 

 izers is effected upon the young sprouts 

 after they leave the seed coat and before 

 they emerge from the soil, while the seeds 

 themselves are injured only slightly or not 

 at all. 



6. It is highly improbable that potash, 

 phosphoric acid, nitrogen or lime used as 

 fertilizers actually favor germination. 



The Pleistocene and Plant Distribution in Iowa. 



Dr. T. H. Macbride. 



This paper offers a new explanation for 

 certain peculiarities of distribution charac- 

 terizing the flora of that prairie State. It 

 appears that certain plants, especially 

 northern species, are not only very rare 

 in Iowa, but are in their distribution lim- 

 ited to very small and far- separated areas. 

 No existing conditions seem to offer any 

 explanation. Recent study of the pleisto- 

 cene geology of the State brings to light, 

 however, the fact that these isolated stations 

 for Iowa's rarer plants are all of them 

 driftless areas, i. e., areas entirely exempt 

 from glacial deposits. So remarkable is the 

 coincidence that we may confidently say 

 that wherever the geologist finds a driftless 

 hill-top there certain plants are sure to 

 occur and vice versa. The paper was illus- 

 trated by a map. 



