Some Realignments in the Genus Nemacladus

Abstract

It has recently been the writer's privilege to examine most of the available herbarium material of Nemacladus, an endemic campanulaceous genus of western North America. In the light afforded by thorough study of this material, it appears that the number of clearly recognizable species is somewhat greater than previously supposed. Fifteen years ago Dr. Philip A. Munzl published a revision of the genus, recognizing three species, with three varieties of one and six varieties of another, making a total of ten named entities. In the present paper there are recognized fourteen entities, grouped under nine species. It may well be that further herbarium study of this difficult genus, supplemented by adequate field studies of its several components, will justify the consideration, as species, of some of these entities here regarded as varieties. The genus Nemacladus offers considerable difficulty to the student because of the superficial resemblance which most of the species bear to each oti-ler. Cauline leaves are almost invariably lacking, and the leaves of the basal rosette are not long-persistent. Plant habit is similar in all the species and sizecharacters prove to be weak and untrustworthy when applied to the plant as a whole or to the vegetative parts in general. The flowers are minute; they rarely exceed five millimeters in length and are usually much smaller than this. In Munz' revision of the genus in 1924, specific limits were determined almost wholly by the use of the characters of the corolla and those of the staminal appendages peculiar to this genus. With the exception of the verv distinct N. longiflorus, all entities recognized by Munz were grouped into two species, each with several varieties. Those plants having Corolla with petals united for 1/3 to 1/2 its length . . stamineal appendages with verv slender transparent cells, which extend straight out from the base so as to appear fan-like were considered as varieties of N. ramosissimus Nuttall, while plants having Corolla with petals united only at very base . . . stamineal appendages with somewhat clavate, rather thick, transparent cells which are at right angles to basal piece were placed together as varieties of N. rigidus Curran.