for the trip, the night being spent in a cave about timber line. The writer ascended the peak over the snow nearly to the top, but was prevented from reaching the actual summit by the violent gale blowing from the east. Many of the species mentioned above as occurring on Popocatepetl were also found on Orizaba (such as Bromus exaltatus, Poa conglomerata, Trisetum spicatum, Festuca amplissima, F. livida, F. tolucensis, Epicampes macroura). Another Festuca (F. hephæstophila) and a species of Calamagrostis were collected. The Festuca grows in small tufts, looking like our sheep's fescue. This and Calamagrostis Schiedeana grew together in the grassy meadows above timber line, the latter in large bunches like Calamagrostis tolucensis. Both have numerous firm involute root leaves, with a papery tawny base peculiar to alpine grasses.

Mt. Nevada was reached on horseback from Zapotlán over a good trail. Two days were taken for this trip, the night being passed in a cabin at about 11,000 feet. The dominant grasses in the upper regions of the timber and extending well above timber line are Calamagrostis tolucensis and Festuca tolucensis, both found on Orizaba. This is interesting as showing the similarity of the flora of the mountain tops as compared with the diversity in the flora of the lower regions. Trisetum spicatum was found throughout the region above timber up to the very summit.

The grasses of the northern Sierra Madre were studied at Sanchez, then the terminus of the railroad from Chihuahua to Topolobampo. This is on the continental divide at an altitude of about 8,000 feet, in the midst of pine forest. The species of grasses found here are in the main different from those found in the other regions mentioned, and the flora shows a close affinity with that of southern Arizona. The dominant grasses are species of Muhlenbergia, Sporobolus and EpicamCertain annual species were especially abundant, such as Sporobolus ramulosus, S. confusus, S. Shepherdii and Muhlenbergia peruviana.

pes.

Grasses of Ponds and Marshes.-The grasses of ponds, marshes, river banks and similar situations occupied by water plants are much the same throughout Mexico. The flora of fresh-water ponds is well illustrated by the grasses seen at Orozco, a station twelve miles south of Guadalajara. Certain species were found only in the water, such as: Panicum paludivagum, with a long narrow inflorescence of several short appressed spikes, and very long submerged rooting stems; Panicum sucosum, with spreading panicle and long submerged stems as in the preceding; Paspalum longicuspe, growing in deep water among water-lilies, only the inflorescence emerged, this consisting of numerous flat spreading spikes, the indefinitely long rooting stems submerged, but floating by means of

A FIELD OF PARÁ GRASS NEAR URUÁPAN. This is a common forage grass at low altitudes in Mexico. Mostly cut and fed green. A native of Brazil.

the large masses of roots at the nodes; Echinochloa holciformis, a tall erect broad-leaved grass, rising well above the water and bearing a close panicle of large long-awned spikelets; Homalocenchrus hexandrus, a small, rather delicate, but wiry grass, with a small panicle of very flat spikelets. Along the edge of the pond, growing in mud or in shallow water, were found Distichlis spicata (salt grass), Paspalum vaginatum, with a pair of spikes at the summit of the slender culm, Echinochloa zelayensis, allied to our barn-yard grass, and Leptochloa fascicularis, with several stiffly ascending spikes.

Distichlis spicata, mentioned above, is a common grass in moist alkaline soil and along the banks of ditches. Another common plant in such situations is Paspalum distichum, which resembles P. vaginatum in having two divergent spikes at the summit. Along the margins of ditches and streams where the soil is not especially alkaline one finds Polypogon elongatus, with slender lax stems and a narrow panicle of small flowers turning yellow with age; Panicum laxum and P. pilosum, small plants with several spikes of small round spikelets, and many species of Paspalum characterized by their plano-convex spikelets. Arundo Donax is a large reed with broad leaves, stems as much as twenty or thirty feet high, and large feathery

plumes when in flower. This reed, introduced from Europe, often grows in dense masses along the banks of irrigation ditches.

Weedy Grasses.-Many of the weedy grasses of cultivated soil and waste places are introduced from the Old World. Others are natives of Mexico or Central America. The following are the more common and widespread species.

The annuals will be mentioned first, as they are the common weeds of cultivated fields: Syntherisma sanguinalis (crabgrass), with spreading stems, hirsute sheaths and slender digitate spikes, common everywhere; Eragrostis mexicana, with a diffuse panicle of lead-colored spikelets, very common in cultivated soil, throughout Mexico; Eragrostis caroliniana, similar to the preceding but with smaller spikelets, less common; Eragrostis ciliaris, with a narrow panicle of strongly ciliate spikelets, a weed of streets in the coastal plain; Panicum fasciculatum, with panicles of round reticulate yellow or dark-brown

spikelets, the main branches spikelike, common in fields at lower altitudes; Panicum hirticaule, with a diffuse panicle, resembling our old witch grass, common at low and medium altitudes on the Pacific slope; Brachiaria plantaginea, with a few spreading spikes of roundish spikelets growing in moist cultivated soil; Leptochloa filiformis, with many slender spreading purple spikes of small spikelets, common in rich fields in the coastal plain; Cenchrus carolinianus and C. echinatus (sandbur), the former with a looser spike of burs, common in fields and waste places; Eleusine indica (goose grass), a smooth grass with a few digitate spikes, found chiefly along streets and in waste places. There are, of course, many other weedy annual grasses, but the above are the commoner kinds.

The perennials are fewer in the number of the species and are found chiefly in pastures and waste places. Chatochloa geniculatus (fox-tail) resembles our northern species, differing in being perennial, one of the few of this class common in cultivated soil. Holcus halepensis (Johnson grass) has obtained a foothold here and there, and may prove a serious pest, as is now the case in Texas and other of our Southern States. Sporobolus Berteroanus (smut grass) can be recognized by its long slender panicle of small flowers that are frequently blackened by a fungus. Certain species of Paspalum are common in meadows, pastures and along roads (P. convexum, P. plicatulum, P. squamulatum). Paspalum conjugatum, with stolons and a pair of long slender spikes, is very common in tropical America and extends into the lowlands of Mexico.

The grasses obtained on this trip yielded one new genus and twelve new species, and in the study of the collection ten more new species were found among the grasses secured by others.