Three new species of Diascia (Scrophulariaceae) from the western Cape

Three annual Diascia species are described from the western Cape. Two species, D maculata K.E. Steiner and D. humilis K.E. Steiner have small flowers and are closely related. D. maculata is characterized by a slightly gibbous corolla with no spurs or sacs, erect stamens, and a distinct patch of oil-secreting trichomes in the tube at the base of each upper and lateral corolla lobe. D. humilis is characterized by a bisaccate corolla, forward projecting stamens and oil-secreting trichomes localized in corolla sacs. The third new species, D hexensis K.E. Steiner, is most similar to D. sacculata Benth.. but it differs from that species by its larger flowers and much longer spurs which curve downward instead of upward.


INTRODUCTION
Diascia section Diascia comprises approximately 41 species of annuals centred in the western Cape of South Africa.This group is currently under revision and has been found to contain many undescribed species.Three new species are described below.
Annual herb, glabrous, simple or branching from the base.Stems up to 220 mm long, erect or decumbent, tetragonal in cross section, up to 1.5 mm on a side.Basal leaves few to many, rosulate or clustered, simple, petiolate, spreading or ascending, lamina 4 -2 3 mm long, ovate to elliptic, apex rounded to acute, base attenuate, margins nearly entire to irregularly lobed or divided, divisions up to ± 3 mm long, oblong-ovate to triangular, entire, acute to acuminate; petioles up to ± 21 mm; stem leaves smaller, becoming reduced upwards, alternate, opposite or verticillate.Flowers axillary, one or two flowers open per stem, nodding in bud, pedicels 22-41 mm long, ascending, broadened and dorsiventrally flattened specially where attached to flower, recurving in fruit.Calyx lobes five, ± equal, ± 2.0-2.5 x 0.8-1.0mm, spreading, or the lateral two slightly reflexed, lanceolate, acuminate, mar gins white ciliate.Corolla bilabiate, limb ± 7.4-10.5 x 8.6-11.0mm; upper lobes ± 2.2-3.0 x 2.0-2.8mm, oblong-ovate, rounded; lateral lobes ± 2.7-3.6 x 2.3-3.4 mm, ovate, rounded, bases oblique; lower lobe ± 3.0-3.9 x 2.9-5.0 mm, obovate, rounded to emarginate.upper lobes yellowish pink distally, bases purplish red with red veins or uniformly reddish purple, other lobes similar in colour but lacking veins, all lobes with dark purple-tipped glandular trichomes, especially on inner surface near the base; tube ± 1.0-2.0mm, reddish purple with yellow spots below upper and lateral lobes, yellow patch below each upper lobe consisting of a single spot or 3 or 4 separate or partially coalesced spots, patch below each lateral lobe a single ± 1 mm long elliptical patch cor responding to a gibbous portion of the tube, yellow patches below lateral and upper lobes-usually separated by a nar row strip of reddish purple tissue, but sometimes consist ing of a single spot spanning the sinus between upper and lateral lobes; gibbous portion of tube with two patches of oil-secreting trichomes, a ± 1 mm long elliptical patch below each lateral lobe and a ± 0.3 mm patch at base of each upper corolla lobe near the sinus with the lateral lobe; spurs or sacs absent; central portion of tube turned out ward to form a boss bearing the stamens, boss ± 1.2-1.5 mm high, connected to the upper lip by a septum.Stamens four, projecting forwards, anticous filaments (appearing posticous due to twisting of the bases) ± 1.5-1.7 mm long, curved and bearing a few scattered trichomes, posticous filaments (appearing anticous) ± 1.2-1.5 mm long, ± straight, widened and bilobed or simply strongly bent backward just below the anthers, anthers ± 0.2-0.5 mm.strongly cohering, yellow, attached to posticous lobes of filaments if bilobed.pollen usually orange.Ovary ± 1.2 x 0.7 mm, ovate in outline with purple markings on upper two thirds to one half, style ± 0.7-0.8mm long, straight, stigma subcapitate, surrounded by anthers, ovules ± 50-55.Capsule ± 4.7-6.0x 2.7-3.0 mm, falciform- ovate in outline, exceeding calyx at maturity; seeds ± 0.65-0.85mm long, dorsal surface ridged, ventral surface with seed coat extended to form a cupule with an oblong elliptical opening.Figure 1.
Flowering tim e: August-October.
Diagnostic features : Diascia maculata is characterized by a slighdy gibbous corolla with no spurs or sacs, stamens that project forwards, and a distinct patch of oil-secreting trichomes (cf.Vogel 1974) in the tube at the base of each upper and lateral corolla lobe.In most populations, there is a yellow spot corresponding to the trichome patches.The pair of spots below one upper and one lateral lobe can be partially confluent or separated by a small strip of reddish purple tissue.The spotting pattern at one locality, the Matroosberg, is slightly different.There, the single elliptical yellow spot below each lobe characteristic of other populations is broken up into several smaller vertically oriented narrowly elliptic spots that are either distinct or only partially confluent.The specific epithet refers to the yellow spotting pattern of the corolla tube.
Diascia maculata is most closely related to D. humilis which has flowers of a similar size and colour.These two species also have very similar capsules, seeds, and pollen colour and can occur sympatrically on recently (less than one year old) burned fynbos (Farm Welkom) and renosterveld (Farm Matroosberg).D. maculata is distinguished most easily from D. humilis by the position of the stamens in relation to the upper corolla lobes, the presence of four distinct oil-secreting trichome patches and the absence of corolla sacs or spurs.The corolla tube of D. maculata is very similar to that of D. gracilis Schltr., since both species are somewhat gibbous; however, in D. gracilis the stamens are erect rather than projecting forward and the long linear capsules are usually more than four times as long as wide, not falciform-ovate and only ± twice as long as wide.
Distribution and habitat: D. maculata ranges from the Hex River Mountains in the southwestern Cape north to the Kamiesberg in Namaqualand (Figure 2).It ranges in elevation from 640 to 1 130 m.Despite its broad geo graphical range, D. maculata is known from relatively few collections.This may be due to overall rarity, a dependence on first year burns or small, easily overlooked, flowers.
Breeding system: D. maculata is autogamous; however, because it secretes floral oil, it may be visited and crosspollinated, at least occasionally, by small short-legged oil-collecting Rediviva bees (Melittidae) (cf.Steiner & Whitehead 1988. 1990. 1991;Whitehead & Steiner 1985).Annual herb, glabrous, simple or branching from the base.Stems up to 250 mm long, erect or decumbent, tetragonal in cross-section, up to 1.5 mm on a side.Basal leaves few to many, rosulate or crowded, simple, petiolate, spreading or ascending; lamina 4-41 mm long, ovate to elliptic, apex rounded to acute, base attenuate, margins nearly entire to irregularly lobed or divided; divisions up to ± 3 mm long, oblong-ovate to narrowly triangular, entire, acute; petioles up to ± 12 mm; stem leaves smaller, becoming reduced and more dissected upwards, 3-verticillate.Flowers axillary, one or two open per stem, nodding in bud, pedicels 16.0-20.5mm long, ascending, broadened and dorsiventrally flattened especially where attached to the flower, recurving, but with the capsule turned up slight ly, in fruit.Calyx lobes five, ± equal, ± 1.8-2.8x 0.7-1.0mm, spreading, lanceolate, acuminate, margins white ciliate.Corolla bilabiate, limb 6.2-7.6 x 7.0-8.6mm; upper lobes ± 1.4-2.5 x 1.7-2.0mm, falciformoblong to oblong-ovate, rounded; lateral lobes ± 2.3-3.0 x 1.9-2.4mm, broadly ovate, rounded, bases oblique; lower lobe 2.4-3.0 x 2.5-3.1 mm, obovate, rounded to emarginate, upper lobes yellowish pink or reddish purple, with red veins at the base, other lobes similar in colour but lacking veins, all lobes with sessile or semi-sessile dark purple glandular trichomes, especially on inner surface near the base; tube ± 1.0-1.5 mm, distended at base of each lateral lobe into a shallow yellow sac, ± 1.8 mm long, sacs containing yellow oil-secreting trichomes, especially near the tips; central portion of tube turned out to form a boss bearing the stamens, boss ± 1.2-1.5 on anticous side and 0.2-0.3mm on posticous side, reddish purple in front and back and yellow on sides, connected to the upper lip by a septum.Stamens four, erect, anticous fila ments (appearing posticous due to twisting of the base), touching the upper corolla lip, ± 2 .0mm long, reddish purple, falciform, glabrous or with a few scattered purple clavate trichomes, posticous filaments (appearing anticous) ± 1.5-1.6 mm.reddish purple.± straight, except just below the anther where there is a sharp nearly 90° bend and broadening of the filament sometimes with a sterile outgrowth in the opposite direction, bend or outgrowth with purple clavate trichomes; anthers ± 0.20-0.30mm, strongly cohering, pale pink or whitish, pollen usually orange.Ovary ± 1.3-1.4x 0.6-1.0mm, ovate in outline, sometimes with purple markings on upper half, style ± 0.70-0.75mm long, straight, stigma surrounded by anthers, ovules ± 40-60.Capsule ± 5.0-6.5 x 2 .6 -3.0 mm, falciform-ovate in outline, exceeding calyx at maturity; seeds ± 0.65-0.90mm long, falciform in outline, dorsal surface ridged, ventral surface with seed coat extended to form a cupule with an oblong-elliptical opening.Figure 3.
Flowering tim e: August-October.
Diagnostic features: D. humilis is characterized by small, usually yellowish pink flowers, its erect stamens, orange to red-orange pollen and small yellow sacs.It is most similar to D. maculata with which it can often be found on burned sites.It can be distinguished from that species most easily by the configuration of its stamens.In D. maculata the stamens project forward away from the upper corolla lip, whereas in D. hum ilis, they are erect with the anthers in a position very close to the upper corolla lip.The yellow markings on the two species also differ.The sacs and sides of the boss in D. humilis are yellow, but there is no discrete spotting pattern as in D. maculata.In D. maculata there are one or several yellow spots at the base of each upper corolla lobe in addition to the yellow spot(s) at the base of the lateral lobes.Associated with the yellow spots at the base of each upper lobe in D. maculata is a patch of oil-secreting trichomes.D. humilis does not have such trichomes in this position.In D. humilis they are contained within each yellow sac.
Distribution and habitat: D. humilis ranges from the Kamiesberg south to Worcester and east through the Little Karoo to Uniondale (Figure 2).It ranges in elevation from 320 to ± 1 200 m and is most commonly found on first year renosterveld or fynbos burns, however it also occurs in short karroid shrublands.Breeding system: D. humilis is autogamous; but like D. maculata it secretes floral oil and may therefore be visited and cross-pollinated, at least occasionally, by small, short legged, oil-collecting Rediviva bees (cf.Steiner & White head 1988, 1990, 1991;Whitehead & Steiner 1985).

G \$ CJH
Annual herb, glabrous, simple or branching from the base.Stems up to 220 mm long, erect or decumbent, tetragonal in cross section, up to 1.5 mm on a side.Basal leaves few to many, rosulate or crowded, simple, petiolate; lamina 8 -3 4 mm long, ovate or obovate to elliptic, apex rounded to acute or apiculate, base attenuate, margins irregularly toothed or occasionally lobed or cleft, lobes or teeth narrowly to broadly triangular, acute to apiculate; petioles up to ± 20 mm long; stem leaves opposite, alternate or verticillate, becoming reduced upwards.Flowers axillary, one flower open per stem, unscented, nodding in bud, pedicels 2 5 -8 0 mm long, ascending, broadened and dorsiventrally flattened especially where attached to the flower, Elongating and ascending or recurved with only the apical portion ascending in fruit.Calyx lobes five, upper three ± equal, ± 3.1-4.0x 0.8-1.2mm, reflexed, lower two somewhat broader ± 3.1-4.1 x 1.2-1.4mm, spreading, all lobes lanceolate, attenuate with white ciliate margins.Corolla bilabiate, limb ± 11.0-15.3x 12.9-17.0mm; upper lobes ± 3.6-4.7 x 4.2-5.0mm, widely ovate to oblong-ovate, rounded to emarginate, bases oblique, lateral lobes ± 4.9-5.1 x 3.8-4.8mm, oblong-ovate, rounded to emar ginate, lower lobe ± 4.8-6.4x 5.8-8.3mm, obcordate, all lobes purple to reddish purple on front and pale purple on back, upper lobes with several darker reddish purple lines at the base, glandular pubescent especially on inside surface; tube, ± 1.0 mm deep, purple to reddish purple inside with 2 or 3 small fusiform to elliptic yellow spots at the base of each upper corolla lobe, spots on outside larger, one or two small ones and one large one or sometimes all confluent and forming a single large spot, tube drawn out below upper lip into 2 spurs ± 9.5-11.5 mm long (measured along the inseam), diverging, projecting backwards and downwards, attenuate, purple to reddish purple, containing clear to light purple, spher ical, multicellular, oil-secreting trichomes in the distal half, sparsely glandular pubescent outside, tube at base of lower lip turned out to form a boss bearing the stamens, boss ± 1.0-1.3mm high on the anticous side and 1.3-1.6 mm high posticous to the stamens, with scattered glandular hairs, connected on the posticous side to the upper lip by a septum.Stamens four, projecting forwards, filaments light purple, anticous filaments (appearing posticous due to twisting of the bases) ± 3.0-3.5 mm long, curved at the base, with scattered purple clavate trichomes on the upper portion, posticous filaments (appearing anticous) ± 2 .5 -2 .9mm long, ± straight, glabrous or with a few purple clavate trichomes; anthers ± 0.3-0.5 mm long, strongly cohering, yellow.Ovary ± 1.75-2.1 X 1.0-1.1 mm, oblong-ovate in outline, style ± 1.5-1.8mm long, ± straight, stigma subcapitate, surrounded by anthers, ovules ± 90-100.Capsule ± 8.7-10.5 x 2.2-2.6 mm, narrowly falcate, ± twice as long as the calyx at maturi ty, seeds ± 0.7-0.8mm long, falciform in outline, dorsal surfaced ridged, ventral surface with seed coat extended to form a cupule with an oblong opening.
Flowering tim e: August-October.
Diagnostic features: D. hexensis is most easily recog nized by its moderately long attenuate corolla spurs, its long narrowly falcate capsule (± 3.5 to 4.5 times as long as wide) and its ovate broadly toothed leaves.Although capsule and leaf shape are similar in D. sacculata, the much longer spurs of D. hexensis clearly distinguish it from that species.
Distribution and habitat : D. hexensis is known only from the southern part of the Roggeveld Mountains west of Sutherland, south to the northern slopes of the Langeberg (Figure 5).It ranges in elevation from 510 m to 1 300 m and occurs in karoo shrublands on relatively moist southfacing slopes.The specific epithet refers to its occurrence next to the Hex River Pass.
Breeding system: D. hexensis is autogamous; but because of its long spurs containing floral oil, it is probably visited and cross-pollinated, at least occasionally, by medium sized oil-collecting Rediviva bees with long forelegs.

FIGURE
FIGURE 2. -Known geographic distribution of D iascia m aculata, A ; and D. humilis.• . in South Africa

FIGURE 5 .
FIGURE 5.-Known distribution of D iascia hexensis in South Africa.