International Excursion in America. 
Valeriana , Mimulus, Galium , Erigerou, with a few European species 
—Pteridium aquiliuum , Cystopteris fragilis, Pyrola minor. 
September 25th was devoted to the ascent of Mount Lemmon 
and a short circuit through the woods on the north side of the main 
range. The southern slopes of Mount Lemmon, from 8,000 to 
9,000 feet, much more exposed to the sun than the valleys like 
Marshall Gulch, are covered with a rather sparse wood of Pinus 
arizouica, with Quercus reticulata, Q. hypoleuca (evergreen), Q. 
Gambelii (a deciduous but leathery-leaved form), and Ceanothus 
Fendleri. This vegetation goes right up to the summit (just over 
9,000 feet) and is very little affected by wind. On the steepest 
faces the pines are few and the ground is mostly occupied by oak 
scrub. The view from the summit of Mount Lemmon is very 
extensive, reaching to the Sonoran mountains in Mexico to the 
south, and the northern Arizona mountains leading up to the Great 
Colorado Plateau on the north. On the north face there is good 
forest of Pseudotsuga and Abies concolor, with many of the same 
species as in Marshall Gulch. 
On September 26th the return journey was made as far as the 
Bear Canyon camp, where it was still very cold at night, though 
the thermometer did not actually go below freezing point. By 
mid-day on the 27th we were back on the baking desert plains 
with shade-temperatures of over 100 n F., returning to Tucson by 
automobile from the foot of the mountains. 
The Santa Catalina trip was in many respects the most 
enjoyable part of the whole tour. The restful days of riding slowly 
through the great pine forests in perfect weather, the glorious, 
ever-changing views, the fine zonation of the vegetation, the 
abundance of interesting plants, and the many talks round the 
camp fire at night with our kind and thoughtful hosts from the 
Desert Laboratory—these things combined to make the week’s 
camping trip an experience impossible to forget. 
New Mexico and Kansas. 
September 28th and 29th were spent in and around Tucson, 
and on the afternoon of the second day we rejoined the main party 
on their return from the Grand Canyon and travelled with them to 
El Paso (Texas) 300 miles to the east, on the Mexican border, where 
we arrived on the morning of September 30th. Here we had a few 
hours to spare, and walked across the dry bed of the Rio Grande 
into the Mexican town of Ciudad Juarez, soon afterwards the scene 
of much bloody fighting. The bulk of the party then continued 
