-120 SECTIONAL rRANSACTIONS.—K*. L. 



related to the forms at present occurring in moist tropical regions. The fossil evidence, 

 however, is not relied on as the main line of attack on the problem of ecological evolu- 

 tion. The detailed evidence from phylogeny is much more convincing. Though 

 general and somewhat speculative schemes of phylogeny for the Angiosperms as a 

 group help but little, yet if attention is directed to the narrower circles of affinity 

 (the well-defined orders, families, and larger genera), all the evidence supports the 

 following conclusions regarding the ecological history of the flowering plants. Within 

 the moist tropics, owing to the great lapse of time and the continued influence of the 

 organic environment or biota, and to a much less extent minor changes of climate, 

 differentiation has resulted in the production of a very large number of trees belonging 

 to a great many separate, usually rather primitive, families, but of a fairly uniform 

 ecological type, with evergreen, somewhat leathery, rather large, usually simple 

 leaves, tall slender sparingly branched stems, often supported by buttresses, thin 

 bark, and hard wood. They show no response to a resting period, and floristically 

 are older than allied derivative types found in colder and drier regions. There have 

 also been produced in the moist tropics large numbers of woody lianes, which connect 

 with the more advanced herbaceous climbers, epiphytes which often connect with 

 the lianes, and hygrophilous undershrubs ai«d herbs. Many terrestrial forest margin 

 herbs, according to recent investigations by Goebel, have velamen on their roots, 

 and this may point to an epiphytic ancestry. All the subordinate tropical types are 

 floristically relatively advanced. 



In the drier sub-tropics (regions with dry winter resting seasons), in still drier 

 semi-desert or desert regions, no one who is well acquainted with the flora can fail to 

 be impressed by the fact that phylogenetically each of the types of plant represented 

 is more recent than the nearly allied moist tropical types. The evolutionary trends 

 are varied, the deciduous habit is usually adopted, the stems are shorter and often 

 stouter, and there is an increase of branching, a decrease of size, their woods are 

 generally softer, and features like thick bark, thorn development, and succulence 

 are common. In general there are responses to the resting season with increased 

 storage of food, and an increase of xerophytism. The warm temperate sclerophyllous 

 woody vegetation of regions with wet winters and dry summers, though derivative, 

 is not always so nearly related floristically to the moist tropical. A mountain origin 

 for this type, probably at least as early as the Cretaceous period, is indicated by 

 various facts, and in this connection it may be recalled that, while most of the great 

 mountain ranges of the present time do not go back as far as the Cretaceous, those 

 of the African continent are as old as the Permian. In this type responses to a resting 

 period are not so well marked. The evergreen habit is retained, but there is a general 

 increase of xerophytism. Hard leaves and deep root systems are general. The 

 cricoid habit has been adopted by a very large number belonging to widely separated 

 circles of affinity. The cold temperate woody plants are very few in number as 

 compared with the others, and the genera are not large. The deciduous types connect 

 with the sub-tropical, their fossil ancestors, where known, were for the most part 

 apparently evergreen ; in regions such as S.E. Asia and Japan, where the record was 

 not interfered with by the Great Ice period, the transitions are gradual. The cold 

 temperate evergreen shrubs, including the heathers, connect rather with the warm 

 temperate sclerophyllous and mountain types of the tropics. In studies on experi- 

 mental morphology, where plant structure is correlated with the basic physiological 

 processes, it seems advisable to pay some attention to phylogenetic history. 



SECTION L.— EDUCATION. 



(For references to the publication elsewhere of communications entered in the 

 following list of Transactions, see page 449.) 



Thursday, August 5. 



1. Dr. Charles Singer. — The Place of History of Science in Education. 



Historical teaching in science may be considered (a) in general education and (b) 

 in the ed\ication of the scientific specialist. It is (a) that is here discussed. 



Sciences are usually taught as systems of absolute knowledge, capable of extension 

 but hardly of correction. This gives a false impression of how the scientific standpoint 

 has been reached. Scientific knowledge is the product of generations of growth along 



