Impatiens matthewiana Ramasubbu & Pandurangan, 2015

Ramasubbu, R., Irudhyaraj, D. Felix, Mohanraj, A. & Pandurangan, A. G., 2015, Impatiens matthewiana, a new scapigerous balsam from Western Ghats, India, Phytotaxa 227 (3), pp. 268-274 : 269-273

Impatiens matthewiana Ramasubbu & Pandurangan sp. nov.

The new species resembles I. scapiflora and I. pseudo-acualis , but differs by having moniliform tubers, rounded leaves, prominently tri-nerved lateral sepals, right basal lobe overlapping or clasping on left one, prominently two spurred lower sepal and 4-aperturate with radial pollen. It differs from I. pseudo-acualis by having larger sized racemes scapes, tri-nerved lateral sepals, 4-aperturate radial pollen grains.

TYPE:— INDIA, Kerala, Idukki District, Lochart Gap (way to Munnar), 10 o 02’ 09.816 N ; 77 o 08’16.783 E ; 1673.64 m asl 25 October 2014, R. Ramasubbu & D. Felix Irudhyaraj, GU 0316 (holotype MH -!, isotypes Gandhigram University Herbarium) .

Scapigerous perennial herb, 47–54 cm high; tuberous, moniliform with three or more jointed tubers, 3.1–4.7× 2.3–2.6 cm. Leaves radical, rounded, fleshy, surface smooth and shining, leaf margin serrate, leaf blade 1–1.5 mm, 4–4.8× 5.3– 5.9 cm, petiole 4.5–8.8 cm; Flowers in racemes scapes, 3.1–4.2 cm across, peduncle, deep purple, many flowered, pedicel 3.2–3.8 cm in flower, 4.3–4.7 cm in fruit, bract broadly ovate, acuminate, violet, 1.3–1.5× 0.5–0.8 cm. Sepals: lateral sepals 2, ovate, acute, 1.1–1.6× 0.4–0.7 cm, prominently tri-nerved, violet. Petals: dorsal petal orbicular, longer than broad, purple, enclosed the entire anthers sac as cap, 0.6–0.9× 0.9–1.2 cm, lateral united petals deeply clawed, 3-lobed, usually the right basal lobe overlapping or clasping on left basal lobe, 1.5–2.2 cm, basal lobe small, oblong, distal lobe oblong, 5.1–6.2× 2.3–3.6 mm, dorsal auricle absent. Lower sepals three, jointed, mucronate, 2.8–3.1× 1.3– 1.6 cm, violet, spur prominently 2, 3–3.6 cm jointed up to middle (occasionally jointed completely), straight or curved inwardly, 0.5–0.8 mm dia. Anthers five, jointed as lobes, crimson striations on the lobe, pollen white. Capsules ovate-oblong, 1.3–1.8× 0.4–0.7 cm, greenish, 11–18 seeded, seeds ovate, brown, 1–1.3 mm long, brown hairs all over the surface, hairs filamentous, closely packed as single stranded helical banding, hairs slender and longer, 5–6 times longer than seeds.

Etymology:—The specific epithet is in honor of Dr. K.M. Matthew, field botanist and Researcher who devoted his entire life period for the taxonomical studies on Flora of Palni hills, Western Ghats and also made extensive field trips to aggregate the floristic wealth of Tamil Nadu, India both in lowland and montane counterparts.

Distribution:—Rare in the hill tops at 1673.64 m asl.

Additional specimens examined (paratypes): — INDIA, Kerala, Idukki District, Lochart Gap (way to Munnar ), 10 o 02’ 09.816 N ; 77 o 08’16.783 E ; 1673.64 m msl, 18 December 2014, R. Ramasubbu & D. Felix Irudhyaraj, GU 0341 (Gandhigram University Herbarium ( GU). INDIA, Kerala, Idukki District, Lochart Gap (way to Munnar ), 10 o 02’ 09.816 N ; 77 o 08’16.783 E ; 1673.64 m msl, 25 January 2015, D. Felix Irudhyaraj & A. Mohanraj, GU 408 ( Gandhigram University Herbarium ) .

Flowering and Fruiting:—September to January.

Notes:— Impatiens matthewiana is a perennial herbs and the tubers perennating year after year. The tubers start to germinate during May–June, flowers at September–October and disappear slowly after the decrease of rains. Impatiens matthewiana grows in superficial soil and crevices of vertical moist cliffs nearby small streams. The species is closely associated with I. goughii Wight , I. viscosa Beddome and I. herbicola Hooker. Altitudinal characteristics, specific climatic condition, soil nature and explicit rainfall force the other orophytic balsams to grow along with I. matthewiana .

No other species of Impatiens in south India possesses as much as taxonomic confusion as scapigerous balsams, more so I. scapiflora and I. acualis . The autecological studies on I. scapiflora and I. acualis revealed it has close morphological similarities in the wing petals, length and morphology of spur and colour of the flower (Bhaskar, 2014). But I. matthewiana has great variation in the morphology of tubers, leaves, lateral sepals, two spurred lip and pollen grains. The floral morphology of I. matthewiana is similar to those in I. scapiflora and I. pseudo-acualis but greatly varies in having its characteristic features ( Table 1.). Bhaskar (2012) studied the morphology of pollen grains of I. scapiflora as 4 or 5–6 colpate and rectangular and the pollen grains of I. pseudo-acualis were reported as 3-colpate and triangular ( Bhaskar and Razi, 1979). But pollen grains of I. matthewiana were reported as strictly 4-colpate, radial and smaller sizes (23–27×31–36 μm).

Bhaskar (2012) also observed greater morphological differences within the flowers of I. balsamina L. and I. balsamina var. parusnathica Hook. f. with 3 spurred flowers along with both lateral sepals metamorphosed and developed into lower sepals and spurs. Further Hooker and Thomson (1860) also recorded morphological dissimilarities in flowers of very few species of Impatiens . But, these morphological variations in the flowers may be due to the hasty appearance of ancestral characters of species of Impatiens or may be due to dysoploidy. However, the specimen collected herewith was observed for a longer period and already collected previously with similar floral morphology. The species retained their characteristic features up to 10 years and the development of two-spurred lower sepal is not due to immediate or mutational effects. Moreover, the specimen is not just distinguished with a single character; it has a greater variation with other species of scapigerous Impatiens by having exclusive characteristic moniliform tubers, prominently tri-nerved lateral sepals, right basal lobe of wing petal overlapping or clasping on left basal lobe, prominently 2-spurs jointed up to middle. The above combination of characters makes determining the relationships of I. matthewiana difficult.