More about Isoetes Lechleri Mett.

Abstract

Material representative of this species is now becoming available from a somewhat extended range in South America, and some of recent collection reveals a tendency to variation in important characters. addition to the plants of Killip and Smith from Colombia, on which was based the variety Colombiana (AMERICAN FERN JOURNAL, Vol. 19, p. 18, et seq.), I have received from Dr. W. R. Maxon the following: Venezuela. Laguna di Apontaderos, Mer. floating on water, January 21st, 1929. H. Pittier, No. 13242. U. S. N. Herb. No. 1440618. These plants have the small corm of the species. The leaves are long and slender, often 30 cm. as compared with the 10-13 cm. of Braun's description for I. Lechleri, and 6-7 cm. for I. Karstenii from Venezuela, which latter was afterwards included in the former. As compared with the var. Colombiana, the tips of the leaves are less acute, and the equatorial ridge of the megaspore is better developed. Diameter of megaspore, 376-517 p. Microspores were not discovered. The velum seems to be complete. Bolivia. La Paz. In einem kleinen See, in der Kordillera. Alt. sobre Mar 4300 m. Dr. Otto Buchstein. No date. U. S. N. Herb. No. 1541653. The corm is small, as usual, and the leaves are about 11 cm. long, bright green, tips brown but not setaceous. Wings at base with some brown color, mostly in lines. Velum apparently complete. Ligule dull salmon, large, ovate, apparently mineralized, brittle. Sporangium thinwalled, small. Megaspores 330-396 p diameter, either pure white or suffused with a pale shade of chocolate brown, mostly smooth, often polished, occasionally slightly wrinkled. The equatorial ridge of medium de129