Gladiolus filiformis , a poorly known species from North West Province , South Africa

Live plants were measured and dissected in the field. Distribution and ecological data were captured with the aid of a Trimble Juno ST, Personal Digital Assistant. Co-ordinates were recorded using datum WGS 84. All data gathered from the biological surveys are stored in a Global Information System database to be incorporated into the planned Biodiversity Information Management System for North West Province.


Introduction
The North West Department of Economic Development, Environment, Conservation and Tourism is presently conducting a biodiversity inventory of the rare, endangered and endemic plants in the province, including Gladiolus filiformis, which is considered to be rare and endangered.
In December 2010, G. filiformis Goldblatt & J.C. Manning was rediscovered by the authors.This species was previously known only from its type locality and was described from a single herbarium specimen (Goldblatt & Manning 1998).
The aim of this article is to expand our knowledge of the morphology, distribution, ecology and conservation status of this poorly known species.

Research method and design
All presently known populations of G. filiformis were surveyed over a period of three flowering seasons, from December 2010 to February 2013.Approximately 300 live plants were examined.
Live plants were measured and dissected in the field.Distribution and ecological data were captured with the aid of a Trimble Juno ST, Personal Digital Assistant.Co-ordinates were recorded using datum WGS 84.All data gathered from the biological surveys are stored in a Global Information System database to be incorporated into the planned Biodiversity Information Management System for North West Province.
Landowners' permission was obtained for this study and no permits were required.Specimens were deposited in the Compton Herbarium (NBG) and Herbarium Soutpansbergensis (ZPB).
The north-western plants, including the type, are smaller than those found to the south-east.The inflorescences of the type specimen have only two flowers but the plant was described as having five flowers.Five flower inflorescences are the lower limit for this species, with the number usually lying between six and ten, with an upper limit of twelve observed.The flowering structure of the type specimen is also smaller than those observed.The perianth tube of the type specimen was stated as approximately 20 mm, whereas the length in the plants studied was found to be between 27.1 mm and 36.5 mm, with the lower and upper limit between 25.4 mm and 40.8 mm.The shape, length and colouration of the dorsal tepals, upper tepals, lower lateral tepals and lower median tepals are described for the first time as they were omitted in the original description of G. filiformis.The rare pink form of G. filiformis has not been recorded before.The unattached outer and median filament sections were found to be of different sizes with the latter usually shorter; this suggests a possible diagnostic feature.No fruiting characteristics were recorded for the species prior to this study.The newly described heteromorphically winged seeds of G. filiformis, with the lateral wings absent or underdeveloped and the apical wing up to 2.4 mm long, are intermediate between the wingless seeds of Gladiolus pretoriensis and the broad, evenly winged seeds of Gladiolus oatesii, which are up to 5 mm long (Lewis, Obermeyer & Barnard 1972).

Related taxa
Gladiolus filiformis has an elongated, recurved, filiform perianth tube, which is diagnostic of the species (Goldblatt & Manning 1998).Gladiolus pretoriensis Kuntze is similar and is also a Southern Bankenveld endemic, but it is usually a smaller plant with smaller pink flowers.Gladiolus pretoriensis fruits are said to be wingless, whilst those of G. filiformis are heteromorphically winged.Gladiolus filiformis could also be confused with G. oatesii Rolfe, but this species has a funnelshaped perianth tube and linear, as opposed to lanceolate, leaves.

Distribution and ecology
The type locality is stated as Gopane Mountains on a rocky koppie, growing in rocky red soil at an altitude of 1100 m.a.s.l.The Gopane Mountains are not indicated on any map, but two towns with the name are.The first reference applies to the remains of an old military base east of Skilpadhek Border Post (2525BC).The whole area around the base is above 1220 m.a.s.l. and we could find no rocky koppie with red soil in the vicinity.The second Gopane is the town in which the Livingston Mission Station (2525BD) is situated.Most of the area is above 1180 m.a.s.l. and there is a rocky koppie to the north-west, with red soil.This koppie is known as Sedukwane (1303 m.a.s.l.).It was on this koppie that we located G. filiformis at an altitude of 1290 m.a.s.l., hence this is most likely the type locality (Figure 2).Peeters, Gericke and Burelli, who collected the type, are therefore most probably in error as it is impossible for G. filiformis to have been collected at an altitude of 1100 m.a.s.l.
Gladiolus filiformis is presently only known from the extreme western sections of the Southern Bankenveld (Partridge et al. 2010), where it grows on hills, hill slopes and plateaus.The plant is not an edaphic specialist, having been observed growing in soils derived from sediments of the Transvaal supergroup, comprising banded ironstone, conglomerate and chert or dolomite areas.The type locality is situated on a dolerite koppie, the remains of a post-Transvaal supergroup volcanic plug.Most populations of G. filiformis occur in grassland, except for those towards its western extremities, including the type locality, which are found in open scrubland.Its presently known distribution, from the north-west (Maphephane) to its south-eastern extremity (Tweefontein), stretches across an expanse of 40 km.
Gladiolus filiformis was found growing sympatrically with Gladiolus permeabilis Delaroche subsp.edulis (Burchell ex a b c