Asparagus prostratus

Status UK Biodiversity Action Plan Priority species. Red Data Book species. IUCN threat category: Endangered (2005). q

C Taxonomy B Magnoliopsida: Liliaceae p Scientific name:

Asparagus prostratus Dumort. Hypanthium Common names: Wild Asparagus, Merllys Gorweddol.

Asparagus prostratus Dumort. (A. officinalis L. subsp. prostratus (Dumort.) Corb.), has often been confused with its close relative A. officinalis L., Cultivated w c Asparagus or Garden Asparagus, Merllys, for taxonomic and nomenclatural reasons. It is now l treated as a full species (Kay et al. 2001), and the two i species are readily identifiable. A D Biology & Distribution p Asparagus prostratus is a long-lived perennial of coastal grasslands, sea cliffs and sand dunes, often in open grassy places but sometimes on rocks or in Figure 1. Measurements of Asparagus. A. Side branch from main stem of A. officinalis. B. Female flower of A. prostratus scrub. There are separate male and female plants. with nearest perianth segments removed to show ovary. C. Male flower of A. prostratus with nearest perianth It is a western European endemic of the coasts of segments removed to show stamens, vestigial ovary and Belgium, Britain, Channel Islands, France, Germany, out-curving perianth segments. D. Fruit of A. prostratus. Ireland, Spain and the Netherlands. Measurements are indicated as follows: c, longest cladode on branch. i, internode on main stem. l, fruit length. p, pedicel length (including stipe). q, perianth length. The distribution in Britain has recently been reviewed w, fruit width. Scale bars are 1 cm in all cases. by Rich et al. (2002). It has been recorded from at least 34 sites in V.c. 1, 2, 9, 13, 41, 45 and 52. It has not been • In the field, the prostrate or decumbent stems recorded recently in six sites (18% decline), is extinct of A. prostratus are instantly different from the in West Sussex and Anglesey and is on the verge of erect stems of A. officinalis. extinction in Dorset. Of the 28 extant populations, • Internode lengths are measured for the lowest nine have fewer than ten plants and only three sites ten internodes, on the main stem, not on the side have more than 100 plants. At least three extant branches (Fig. 1a). colonies are declining. • Longest cladode (needle-leaves) length is measured as the longest on up to each of ten Identification & Field survey branches (Fig. 1a). Note that there is at least one Asparagus prostratus can be a very difficult species to form of A. officinalis with very short cladodes see amongst other vegetation, the two best times to but long internodes (possibly referable to var. survey being May-June before other vegetation grows sulcatifolius). up, and in autumn when the berries ripen red and • Pedicel length is measured from the stem to the senescent plants turn yellow. base of the hypanthium (including the stipe) on up to ten open flowers/fruits on each plant (Fig. 1d). Key characters • Perianth segments are measured from the base of The characters separating them are given in Table the hypanthium to the tip of the longest perianth 1 (see also Figure 1). Averages should be calculated segment (Fig. 1b,c) on up to ten dried flowers from 5-10 different measurements. (these are likely to have shrunk in size compared to fresh flowers). Differentiation from similar species

TABLE 1. CHARACTERS DISTINGUISHING ASPARAGUS OFFICINALIS AND A. PROSTRATUS Asparagus officinalis Asparagus prostratus Stems (40-)80-200 cm tall, erect, straight Stems 10-70(-130) cm tall, at least the (sometimes sinuous towards apex), largest usually prostrate, decumbent or usually mid- to olive-green or ascending, rarely erect with tops curving yellowish-green, often shiny. sideways, usually curved and/or sinuous, usually glaucous (especially when exposed), sometimes green. (Figure 2). Internode length Mean 12-36 mm (range of all Mean 3-15(-20, exceptionally -50) mm (range internodes 4-89 mm). of all internodes 2-50 (exceptionally 150) mm). Longest cladodes Mean length (6-)10-32 mm (range 4.5- Mean length 2-16(-18) mm (range 2-24 mm), (needle leaves) on 34 mm), often curved, thin, flexible. straighter, often stout and rigid. branches Pedicels Mean pedicel length (6-)7-15 mm Mean length 3.2-10.4 mm (range 2-13 mm). (range 5-17(-25) mm).

Male perianth Mean length 4.0-5.7 mm (range 3.8-7 Mean length 4.7-8.0 mm (range 4.2-8.3 mm), mm), yellow (rarely flushed pinkish), often reddish or copper-flushed yellow, out- tips straight. curved at tip.

Female perianth Mean length 3.1-4.1 mm (range 2.7- Mean length 3.5-5.9 mm (range 3.3-7.5 mm), 4.3 mm), pale yellowish-green, tips yellow to whitish-green, out-curved at tips. straight.

Figure 2. Cultivated plant showing prostrate growth habit, glaucous colour and short cladodes (needle-leaves). References Rich, T. C. G., Rich, L. K., Evans, S. B., Evans, A. E. Kay, Q. O. N., Davies, E. W. & T. C. G. Rich (2001). & Hopkins, F. (2006). Vegetation and habitats of the Taxonomy of the western European endemic western European endemic Asparagus prostratus Asparagus prostratus (A. officinalis subsp. prostratus) Dumort. (Asparagaceae), Wild Asparagus. Pp. 231-241, (Asparagaceae). Botanical Journal of the Linnean Society in Leach, S. J., Page, C. N., Peytoureau, Y. & Sanford, 137: 127-137. M. N. Botanical Links in the Atlantic Arc. BSBI Rich, T. C. G., Bennallick, I. J., Cordrey, L., Kay, Q. O. Conference Report no. 24. BSBI/English Nature, N., Lockton, A. & Rich, L. K. (2002). Distribution and London. population sizes of Asparagus prostratus Dumort., Wild Additional photographs are available on the ARKive Asparagus, in Britain. Watsonia 24: 183-192. website (http://www.arkive.org/species).