554 



SCIENCE 



[N. S. Vol. L. No. 1303 



It is not impossible to make plant evolution 

 the central axis around wMch to swing a 

 high-scliool course in botany. High-school 

 pupils can be trained in this sort of dis- 

 cipline, but it usually involves the wooden 

 adherence to a few " types " illustrating a 

 supposed evolutionary series, and imposes 

 severe limitations upon a student's concep- 

 tions of plants, no less detrimental in its 

 effect upon his mind than the rigid con- 

 ceptions of " typical " plants, and the stereo- 

 typed leaf and flower forms of the pseudo- 

 morphology of the older school. The phy- 

 logenetic method of teaching botany to 

 elementary students, is not only objectionable 

 because it deals with plants which are almost 

 throughout entirely unrelated either to their 

 previous experience and observation, or to 

 their future necessities, but because, as ordi- 

 narily handled, the data are confined to a 

 comparatively few type plants because of the 

 time restrictions imposed. The result is, that 

 instead of widening his horizon of the plant 

 world, the succession of forms worked upon, 

 serve chiefly as mnemonic beads in a botan- 

 ical rosary, the telling of which serves to call 

 up memorized facts for examination purposes, 

 chiefly concerning reproduction. 



At the present time, the teaching of botany 

 in secondary schools is quite generally mor- 

 phological in character, a survey of the gen- 

 eral morphology and reproduction of the 

 great groups of plants in succession. This is 

 done partly by virtue of tradition, and partly 

 because the subject is most easily handled in 

 that way under average conditions. In too 

 many cases however, this sort of teaching 

 degenerates into a sort of stereotyped routine, 

 revolving around the peculiar relations of the 

 alternating generations in plants — the tragic 

 story of the decline and fall of the gameto- 

 phyte and the triumphant rise of the sporo- 

 phyte. This rather extensive and various 

 history has become condensed and standard- 

 ized for teaching purposes into an orthodox 

 version, to the correct rendition of which a 

 few selected forms of plant life are annually 

 consecrated. Beginning with the microscopic, 

 unicellular forms of green algse, we proceed, 

 with side excursions into the equally micro- 



scopic blue-greens, up through colonies, fiat, 

 globular, and in chains and filaments, until 

 we finally get to a real alga that we can 

 plainly see with the 1/6 objective. From 

 here on, the pathway leads finally to where 

 Fucus vesiculosus and Polysiphonia violacea 

 are "waiting to tell their tale of the alter- 

 nation of generations and heterospory. Once 

 in the clutches of these two ideas, botanical 

 anxiety for the student begins, for he is there 

 to stay. 



We are now, however, compelled to divert 

 our attention for a time from green evolution 

 in order to pick our way over the fungi, after 

 which we duly return to our duty of securing 

 the transition in the laboratory from water 

 to land life, whereby there emerges, with 

 dripping rhizoids, a liverwort upon the mud. 



The Bryophytes, unfortunately, are still very 

 small plants, and usually do not of their own 

 motion excite undue interest among young 

 people. However, this is not for us to dis- 

 cuss, to be sure, since it becomes our respon- 

 sibility for the next few weeks, to make the 

 curious and rather minute relations of the 

 gametophyte and sporophyte series in this 

 group the chief object of our ambition. 

 There is many a beginning student who has 

 been led during this period of his life to sup- 

 pose that botany thinks a great deal of 

 Marchantia polymorpha. Bidding farewell at 

 length to the Hepatieae, we become greatly 

 obliged to the botanical supply company for 

 its fruiting Sphagnum and its Polytrichum 

 commune, whereby we are enabled to continue 

 the ever-lengthening story of the everlength- 

 ening sporophyte and its ever-diminishing 

 spores. 



The leafy gametophyte of the Bryophytes 

 has now to roll up its foliar organs and be 

 born again like unto a liverwort, re-emerging 

 before the student as the prothallium of the 

 ferns. We have now at last gotten roots on 

 the sporophyte, and its future is assured, so 

 that we can henceforth proceed to devote oixr 

 remaining attention to prosecuting our fa- 

 vorite microscopic pursuit of the luckless and 

 reticent gametophyte, as it elusively recedes 

 from form to form, through Marsilia, Salvinia 

 and Pinus Laricio, until its final recondite 



