ABNORMAL GROWTHS. 51 



which the testa of the seeds of most of the Abietiness is expanded; 

 is evidently designed as an aid to their dispersion by the wind. Soon 

 after the maturation of the cones, the persistent scales fall backwards 

 or outwards from the axis to permit the ripened seed to escape. The 

 scales are very sensitive to moisture, and in many species exhibit 

 rapid movements when wet. This is especially well seen in the cones 

 of Tsuga canadensis in which the widely open scales become completely 

 closed in twelve minutes. This property of the cone-scales is found 

 to be very efficient, first in loosening the winged seeds from the 

 scales which bear them, and secondly in favouring the wide dispersion 

 of the seeds, as the cones open and close many times before all the 

 seeds are sown, thus securing their transport in different directions by 

 the varying winds.* 



The seeds of each species produce plants "after its kind," but 

 innumerable departures from a fixed type are of constant occurrence, 

 and many of them so remarkable, that were their origin unknown 

 they would, on superficial glance, be taken for quite distinct species. 

 Among such may be noted the Irish Yew, Clanbrasil's Fir, the erect 

 Lawson's Cypress, and the Whipcord Arbor Vitae. Besides these, which 

 may be called extreme forms, every bed of seedling plants shows 

 numberless variations in habit, foliage or some minor particular. 

 Taxads and Conifers therefore, like many of the lower forms of 

 vegetation as Ferns, are polymorphous, a principle that manifests itself 

 throughout the Order, but is much more common in some tribes than 

 in others ; it is less frequent in Pinus than in Abies, very usual 

 in the Yew, and most common in the Cypress tribe (Cupressus, 

 Thuia, Juniperus, etc.). It is most observable in plants in their 

 young state, but when the departure from the usual type is not very 

 great the difference gradually disappears as the plant becomes older. 



ABNORMAL GROWTHS. 



EXCEPTIONAL formations or deviations from the ordinary mode of growth, 

 or monstrosities as they are called, are of frequent occurrence among 

 Taxads and Conifers. Many such malformations are due to diseases 

 caused by fungi, the attacks of insects and other animals, and even 

 to the operations of Nature as winds, storms, etc. Those due to 

 diseases and insect agency are treated of under their respective 

 heads ; but there are some which cannot be traced to either cause, 

 and which require separate notice. For the following selected 

 instances the author is almost wholly indebted to Dr. Maxwell Masters, 

 the eminent authority on vegetable Teratology, from whose writings on 

 the subject .they have been extracted. 



The malformations occurring amongst Taxads and Conifers not 

 caused by disease or insects may be grouped under several distinct 

 headings, but by far the greater number of observed instances are 

 referable to the following : 



O 



I. ANDROGYNY in which both sexes occur in the same axis or 

 parts of the same cone. 



* Prentice in Botanical Gazette, 1888, pp. 236, 237. 



