Chrysopogon densipaniculatus Landge & A.P.Tiwari, 2022

Tiwari, Arjun Prasad & Landge, Shahid Nawaz, 2022, Chrysopogon densipaniculatus (Poaceae: Andropogoneae): a new species from India, Phytotaxa 538 (3), pp. 241-248 : 242-245

publication ID	https://doi.org/ 10.11646/phytotaxa.538.3.7
DOI	https://doi.org/10.5281/zenodo.6338145
persistent identifier	https://treatment.plazi.org/id/2B4687FA-1E39-FFF0-FF48-FD6F080FFD6F
treatment provided by	Plazi
scientific name	Chrysopogon densipaniculatus Landge & A.P.Tiwari
status	sp. nov.

Treatment

Chrysopogon densipaniculatus Landge & A.P.Tiwari , sp. nov. ( Figs. 1 View FIGURE 1 & 2 View FIGURE 2 )

Diagnosis:—It is a very distinct species, may easily be distinguished by the presence of transverse glandular patches on the laterally compressed peduncle; very dense panicle inflorescence i.e. 15 × 8.0 (–10) cm; 35–76 racemes from the lower nodes on rhachis; rhachis terminally divided; leaf blades ca. 90 × 2.0 cm, indistinct from the sheath (quite continuous); sheaths distinctly terete not keeled; lemma and palea in the pedicelled spikelet bi-dentate to tridentate, the latter of which is reduced to a minute scale, ca. 1.0 mm long.

Type:— INDIA. Chhattisgarh, Korba district, Chaiturgarh hills, 22°30’ 50.1” N lat. and 82°16’ 41.5” E long., ca. 898 m above sea level, 11 November 2019, A. P. Tiwari 21 (holotype: BLAT; isotype: BLAT) GoogleMaps .

Description

Perennial, tall, glaucous, unbranched (if branched then sparsely), robust herb. Culms glabrous, erect, not ascending, 150–210 cm high, as thick as a little finger at the base, terete; cataphylls at base several and woody, ovate-lanceolate, 2.0– 2.3 cm long, glabrous, vernicose, pungent, ribbed, laterally compressed and convex on the back. Sheath glabrous, tightly clasping the culm, longer than the internodes (at least the basal one) upper ones shorter, keel-less (terete), ribbed, indistinct from the blade, 10–17 cm long. Ligule reduced to a minute rim of dense white hairs, up to 0.8 mm long. Blades oblong-lanceolate, ca. 90 × 2.0 cm, glaucous, glabrous, scabrous, margin minutely pectinate, multinerved (up to 24 nerves), apex acuminate, mid-nerve prominently broad, pale yellowish, dilated base-wards, base broad, sub-cordate at the base. Inflorescence a pyramidal dense panicle, congested, with 35–76 spiciform-racemes on each node along the tough, inarticulate rhachis (central axis); rhachis consists of up to 12 nodes, terminally divided into 1–3 secondary branches bearing few racemes; peduncle laterally compressed, flexuous, scabrid, sometimes with distinct glandular bands in long discrete patches; panicle up to 15 cm long and 8 (–10) cm wide when spread (broadest at/near the base). Raceme consists of triad of spikelets in which one is sessile (hermaphrodite) and two pedicelled (barren or staminate) on a long, slender, scaberulous, rhachis internode up to 0.5–5.3 (–6.0) cm long (tip, when raceme disarticulates, is somewhat swollen, oblique, excavated and bearded with brownish hairs); few racemes at the lowest node are either reduced or depauperate, but distinctly hairy. Sessile spikelet: ca. 6.0 mm long (excluding a pungent callus ca. 1.0 mm long with dark brown hairs), laterally compressed, hermaphrodite; lower glume ca. 5.0 × 1.2 mm (spread out), oblong-elliptic, broader little above the middle, laterally compressed, slightly keeled but mostly rounded, apex acute, somewhat setose downwards, somewhat herbaceous, 4-nerved (green), margin hyaline, ciliolate (hairs caducous), surface scabrous; upper glume ca. 6.0 × 2.3 mm (spread out), elliptic, laterally compressed, curved, subcoriaceous on the obtuse keel broader near the base, sparsely hairy (hairs not brownish) in the middle or not, 1-nerved on either side of a keel, ciliolate, scabrous, setaceous near the tip and somewhat over the arista with white hairs (arista ca. 7.0 mm long) but near the base only, awn slender, scaberulous not twisted; lower lemma equal to the lower glume, elliptic, epaleate, barren, hyaline, membranous, 2-nerved, margin ciliate, tip acute; upper lemma linear 4.5–5.0 mm long, epaleate, distinctly bi-lobed, glabrous, hyaline-membranous with a geniculate awn issuing from the sinus, ca. 26 mm long (column puberulous 8.0–9.0 mm long (brownish) and bristle scaberulous 15–17 mm long (pale yellow)); stamens 3, anthers 3.0– 3.2 mm long, orangish (when dried); stigma densely plumose, laterally exserted from below the middle in the sessile spikelet; caryopsis not seen. Pedicelled spikelet equal to the sessile, ca. 6.0 mm long, sparsely hairy, scabrid, awned, staminate or barren; pedicel flattened, 2.0– 2.2 mm long (confluent into the callus of the sessile spikelet), less than half as long as the sessile spikelet, ciliate on both the angles with brownish hairs (hairs towards the apex reaching 4.0 mm in length and reduce downwards); lower glume ca. 6.0 × 1.8 mm, elliptic, broadest little below the middle, aristate (3.0–5.0 mm long, scaberulous, pale yellow), herbaceous, membranous, 7-nerved (green) evanescent downwards, hairy and scabrous on the dorsal side, slightly purplish; upper glume ca. 5.5 × 1.8 mm, elliptic, acute, sub-hyaline-membranous, 3-nerved, margin ciliate, inflexed, rounded on the keels, with a slight tinge of purple; lower lemma ca. 5.5 × 1.1–1.2 mm, oblong-elliptic, acute, epaleate, barren, hyaline-membranous, 2-nerved, margin hairy; upper floret staminate; upper lemma ca. 5.0 × 1.0 mm, oblong-sub-elliptic, paleate, staminate, margin ciliate, hyaline, membranous, distinctly 1-nerved, tip bifid (lobes ca. 0.5 mm long), lobes acute ciliolate or glabrous; palea ca. 0.7–1.0 mm long, oblong or somewhat elliptic or not, nerveless, glabrous, apex acute to bidentate or irregularly tridentate, hyaline tiny reduced scale; stamens 3, anthers 3.0– 3.5 mm long.

Etymology:—The epithet “ densipaniculatus ” alludes to the nature of highly dense panicle inflorescence.

Distribution:— Chhattisgarh, Korba district, Chaiturgarh hills, India. Hitherto, it is the only locality where this species occurs, apparently endemic to the region.

Habitats and associated species:—In dry sal forest on rocky hill slopes at an altitude of 898 m. where it grows along with other grass species, such as: Apluda mutica Linnaeus (1753: 82) , Capillipedium assimile (Steudel 1855: 397) Camus (1922: 314) , Heteropogon contortus (Linnaeus 1753: 1045) Beauvois ex Roemer & Schultes (1817: 836) , Indochloa clarkei (Hackel 1891: 49) Bor (1954: 76) , Oplismenus compositus (Linnaeus 1753: 57) P. Beauvois (1812:54) and Panicum notatum Retzius (1786: 18) .

Flowering & Fruiting:—October to December.

Conservation Status:—Hitherto, Chrysopogon densipaniculatus is only known from the type locality where about 50 mature individuals were observed. The species is confined to an area of less than 5.0 km 2 on rocky hills of Chaiturgarh which are prone to local tourism and grazing. Since, the population is located on the roadside and regular movement of the vehicles may cause a serious disturbance in the habitats and which is capable of making the population vulnerable to destruction. According to IUCN (2016) criteria the species is classified as Critically Endangered (CR), based on the criteria B2b (i,ii,iii) and D. Nevertheless, further explorations and studies are required to ascertain its current status.

Note:—It can be easily segregated from the other species of Chrysopogon in transverse-glandular bands on the peduncle, 35–76 racemes emerging from the lower nodes of central axis of the panicle. Moreover, the character of bifid upper lemma and acute to bidentate or tridentate reduced palea of pedicelled spikelet are quite unique features may be reported first time in the genus. The central axis of the panicle is terminally further divided into 2 to 3 secondary branches or rhachises (each branch comprises 1 to 2 nodes) that in turn bear racemes in the whorls. Sometimes these secondary branches bear only 2 racemes on highly reduced rhachis internodes, appearing almost sessile. For the detailed comparison with an allied species, refer to ( TABLE 1 View TABLE 1 ).