488 BOTANICAL GAZETTE (MAY 
light intensity 1.75:100; evaporating power of the air 1:2.3; humidity up to 
100:84; wind velocity 1:2.2; and temperature from 1° to 2° C. higher at the 
latter position. Green and dry weights of leaves in the center of the crown 
were 46 and 38 per cent respectively of equal areas at the south periphery, 
while cross-sections showed differences of structure as great as those of weight, 
the average thickness of the centrally placed leaves being only 38 per cent of 
those at the periphery. The other species studied showed variations quite as 
interesting as those cited, the loss of water by transpiration showing a range 
of 3-12 times as je from leaves upon the south periphery as from equal leaf 
areas within the crown. 
The ercrantios is particularly important in opening up a field of promis- 
' ing and almost unlimited possibilities in the study of structural response of 
aérial organs to measured variations in external factors —Gro. D. FULLER. 
Vegetation of Dutch Guinea.— Miss Gripss” has added to her contributions 
to our knowledge of little known floras by exploring portions of the mountain- 
ous parts of Dutch N.W. New Guinea. The plant formations receiving most 
attention were the low mountain forest above 7000 ft., in which the dominant 
trees were Quercus Lauterbachii, Podocarpus Rumphii, P. papuanus, and Phyl- 
locladus hypophyllus. These attained a height of some 16 m., with plenty of 
lianas, among which such ferns as Gleichenia linearis, Nephrolepis acuminata, 
and Polybotrya arfakensis were conspicuous. There were transitions to a mossy 
forest in which to the preceding trees there were added, among others, Dacry- 
dium novo-guineense and Librocedrus arfakensis, making a remarkable aggregate 
of conifers, together with Drimys arfakensis and several Myrtaceae. Here a 
rich undergrowth of mosses, ferns, and herbaceous plants combined with an 
abundance of many epiphytic ferns and orchids. Locally in marshy localities 
there were found pure stands of the endemic Araucaria Beccarii. With increas- 
ing altitude the mossy forest decreased in height, although many of the same 
tree species persisted, with the addition of species of Rhododendron and several 
other ericaceous shrubs, as the mountain crest of g000 ft. was reached. Here 
the trees were low and scrubby, the stand more open, and the growth of under- 
shrubs more dense. 
Miss Grpps has recorded many interesting incidents of her trip and 
described less minutely other plant associations, but declares that she saw no 
forest that answered to the description of rain forest. Her collections showed 
330 species, of which roo were hitherto unknown; they included in addition 
5 new genera.—Geo. D. FULLER. 
Verbascum hybrids.—It has long been known that many hybrids occur in 
the genus Verbascum. FOCKE, SCHIFFNER, and others have made observations 
* Grpss, LILIAN S., A contribution to the phytogeography and flora of the Arfak 
Mountains, etc. Dutch N.W. New Guinea. 8vo. pp. iv+226. pls. 4. figs. 16. Lon- 
don: Taylor and Francis. 1917. 12/6. 
