Contribution to the knowledge of the genus Stachys in the province of Tucumán

Abstract

This paper deals with anatomic and cariologic observations on the species Stachys petiolosa Briq., in which samples from the plain of the province of Tucuman were used.

The anatomic observations include the study of the root, stem and leaf. The chromosomic recounts were performed on the root apex meristematic cells and on the pollen of the mother cells.

The authors arrive at the following conclusions:

A) Anatomic observations. Trichomes with pluricellular hairs of three types: a) with a head, one celled peduncle inside the epidermis; b) with a head, pluricellular peduncle somewhat emergent on the epidermal cells; c) simple, rigid, single seried. Root. No pith is seen, the xylem being central. Stem. It is quadrangular in its trans versal cut, crossed along its longitude by four awes which belong to four collateral fascicles. Leaves, Somata of the caryophyllaceous type. Bifacial mesophyll. Semicircular petiole in the transversal cut, with a main central fascicle and two small lateral ones.

B) Cariologic observations. The number of chromosomic set is n: 16 and 2n: 32 being the chromosomes type metacentric and submetacentric.

C) The key proposed by Epling to separate Stachys petiolosa Briq. from S. gilliesii Benth. is not adequate for delimiting these species in the Northwest of Argentina. Ten figures are joined by.