290 



SCIENCE 



[N. S. Vol. XXXIX. No. 999 



therefore of value in classification. In the Coni- 

 fers the foliar supply leaves only a single gap in 

 the cylinder, but in the lower Angiosperms the 

 several traces which supply every leaf come off 

 from the stele some distance apart and each causes 

 a gap of its own. The primitive number of foliar 

 traces and corresponding gaps among Angio- 

 sperms seems to have been three. This is charac- 

 teristic of the Amentiferse, the simpler Eanales, 

 the Urticales and the Bosales. It also persists in 

 some of the higher orders, such as the Capri- 

 foliacefe and Compositfe. In other groups, this 

 condition has been amplified into one with a large 

 number ef strands and gaps, as in the Magnoliacese, 

 the Polygonales, the Araliales and the Monocoty- 

 ledons. In still others the three gaps have become 

 approximated and merged into one, as in the Cen- 

 trospermae, Myrtales, Erieales, Ebenales and Tubi- 

 florae. The great simplicity of these nodal char- 

 acters and their uniformity throughout such large 

 groups of plants make them of much value in de- 

 termining broad lines of relationship. 



Primitive Characters Recalled by the Chestnut- 

 harh Disease and Other Stimuli: 1. W. Bailey 

 and J. S. Ames. 



Dicotyledonous leaves with entire margins pre- 

 dominate in tropical regions, but are compara- 

 tively infrequent in boreal and mountainous re- 

 gions. Subtropical and tropical representatives of 

 boreal families have commonly entire leaves. 

 Deeply lobed, dentate or serrate leaves are char- 

 acteristic of Fagales endemic in northern latitudes. 

 Toward the tropics the margins of the leaves be- 

 come progressively entire. It seems probable that 

 all living representatives, at least, of the Fagales, 

 are descendants of boreal or mountainous forms, 

 since vestiges of lobes, dentations and serrations 

 persist upon young vigorous plants of subtropical 

 species. Furthermore, the boreal type of foliage 

 is recalled in mature parts of these plants by the 

 stimulating effects of very rapid vigorous growth 

 and the irritating effects produced by the attacks 

 of insects and fungi. A striking illustration of 

 these phenomena is afforded by the common Amer- 

 ican chestnut, Castanea dentata Borkh. Foliage 

 formed subsequent to severe infections of the 

 chestnut-bark disease {Endothia parasitica Mur- 

 rill) is typically oak-like, frequently resembling 

 ■closely Quercus rubra L. The reversion is not con- 

 fined, however, to external characters. For the 

 ■wood formed by the diseased cambium possesses 

 anatomical structures which are a characteristic 

 feature of the genus Quercus. 



The Archegonimm of Sphagnum subsecundum: 



Geokge S. Beyan. 



Sphagnum subsecundum, where studied in the 

 region near Chicago for the past two autumns, 

 has been found to bear enormous numbers of sex 

 organs. The arcbegonial and antheridial heads are 

 not difiieult to recognize, and may be easily dis- 

 tinguished from each other. 



A careful study brings out the following facts, 

 as a general statement, in regard to the develop- 

 ment of the archegonium. Arohegonia are found 

 to occur terminally on short side branches which 

 rise near the apex of the main stem. The apical 

 cell of one of these branches becomes an arcbe- 

 gonial primordium in which oblique walls appear. 

 The cell above these walls produces the primary 

 archegonium ; while each lateral segment cut off by 

 them forms a secondary archegonium. In the 

 archegonium initial the first wall is transverse, and 

 usually subsequent transverse apical divisions give 

 rise to a filament of cells varying in number from 

 four to six. In each cell of the filament secondary 

 divisions occur. Finally the apical cell of the fila- 

 ment enlarges and oblique walls, followed by a 

 transverse wall, cut out a cover cell and a central 

 cell. The cover cell forms chiefly the cap of the 

 archegonium, while the central cell on division 

 produces a primary canal cell and a ventral cell. 

 The primary neck canal cell gives rise to a veritable 

 number of neck canal cells, frequently from six 

 to eight. The ventral cell divides very late, form- 

 ing the ventral canal cell and the egg. Usually 

 just after this latter division the neck canal cells 

 break down, but the ventral canal cell is persistent, 

 rounding off and coming to lie in the venter near 

 the egg, from which it may be distinguished by its 

 slightly smaller size. Shortly before fertilization 

 the ventral canal cell goes to pieces. 



So-called abnormalities occur. Two eggs and 

 two ventral canal cells occur occasionally, whUe 

 in one case a large venter was found in which were 

 ten such cells. 



On the Structure and Melationships of Macro- 

 glossum: D. H. Campbell. 



Macroglossum Copeland is a genus of Marat- 

 tiacese, founded upon a species, M. Alidce, sent 

 from Sarawak in Borneo. The writer collected it 

 at two stations in February, 1913, and secured ma- 

 terial of both sporophyte and gametophyte. 

 Another species was found growing in the botan- 

 ical gardens of Buitenzorg, under the name Angi- 

 opteris Smithii Eaeiborski. The origin of this lat- 



