A TAXONOMIC REVISION OF AMORPHOPHALLUS BLUME EX DECNE . SECT . CONOPHALLUS ( SCHOTT ) ENGL . ( ARACEAE ) IN INDIA

The diagnostic characters of Amorphophallus Blume ex Decne. sect. Conophallus (Schott) Engl. is amended based on detailed studies of characteristics of the constituent species. In India the section is represented by six species, viz. A. bognerianus Sivad. et Jaleel, A. bulbifer (Sims) Blume, A. carnosus Engl., A. commutatus (Schott) Engl., A. nicolsonianus Sivad. and A. oncophyllus Prain ex Hook. f. The species A. commutatus forms a complex with three varieties, viz. var. commutatus, var. anmodensis Sivad. et Jaleel, and var. wayanadensis Sivad. et Jaleel. Keys to the species and varieties have been provided to facilitate easy identification. Amorphophallus carnosus has been rediscovered after more than 100 years of its first discovery and collection. Amorphophallus bulbifer has comparatively wider distribution in India with extended distribution in Bangladesh and Myanmar. The species A. bognerianus, A. carnosus, A. commutatus, A. nicolsonianus and A. oncophyllus are exclusive endemics of India.


Introduction
The genus Amorphophallus Blume ex Decne. is represented by more than 200 species (Mayo et al., 1997;Jaleel et al., 2011).Engler (1911) recognized 11 sections under the genus based on 78 species, and additional 12 species were treated as doubtful or not at all known.Many new species have been discovered and recognized since then.The sectional classification of Engler (1911) has several drawbacks as per the present taxonomic standards.A brief account on the taxonomic history of Indian species of Amorphophallus has very recently been provided by Jaleel et al. (2011) and it contained reference to earlier relevant works of Hooker (1894), Bogner et al. (1985), Sivadasan (1986Sivadasan ( , 1989)), Sivadasan et al. (1994), Hetterscheid et al. (1994), Bogner (1995), Mayo et al. (1997), Sivadasan and Jaleel (1998a, b, 2000a, b, 2001, 2009) and Yadav et al. (2009).The genus is reported to be under revision and is supposed to include pollen morphology, odour biochemistry and pollination biology, and molecular data (Van der Ham et al., 2005).
In India the genus is represented by 3 sections (sensu Engler, 1911), and revision of one of the three sections, viz.Amorphophallus sect.Rhaphiophallus which is the largest in India has been published recently (Jaleel et al., 2011).The present paper deals with revision of Amorphophallus sect.Conophallus (Schott) Engl.which is the second largest in India.As the present revisionary study deals with the species confined only to India and a worldwide revision of the genus is expected to ensue, any attempt on sectional re-classification based on Indian taxa would be inappropriate, and hence the sectional name as used by Engler is retained here for convenience with amendments to the diagnostic characters of the section under study.

Materials and Methods
Exhaustive field explorations were made all over India including the Andaman and Nicobar Islands at different seasons for collection of specimens in vegetative and reproductive phases; and all relevant data have been recorded, and photographs taken.The present taxonomic revision was based on both the specimens collected during the study and those available in major Indian and international herbaria.The methodology as mentioned by Jaleel et al. (2011) has been followed.Specimens of Indian species available at various major Indian and International herbaria, viz.ASSAM, BSA, BSD, BSHC, BSI, CAL, CALI, DD, GH, JCB, K, KFRI, L, M, MH, PBL, TBGT and US were examined; but citations were limited to few representative specimens to restrict the length of the article.
Type: Amorphophallus campanulatus Decne.Tuberous herbs; tubers subglobose, globose, depressed-globose, cylindric or obconoid.Leaves solitary; lamina with leaflets sessile or rarely petioluled, base usually unequal and decurrent on rachis or not; venation reticulate with secondary lateral veins united below margin forming sub-marginal collective vein.Flowering without leaves; inflorescence with peduncle short or long, usually identical with petiole in colour and pattern of mottling, basally surrounded by 3-7 cataphylls; spathe with a basal convolute tube and erect or bent limb.Spadix long or shorter than spathe, usually non-stipitate or stipitate, with a basal female zone, a continuous middle male zone, and a terminal sterile appendix.Female flowers crowded, spirally or subspirally arranged, ovary 1-3-locular, stigma sessile, or very short styled, entire or lobed; ovule 1 per locule.Male flowers free, dense; dehiscence by apical slit or pore.Spadix-appendix erect, elongate-ovoid, ellipsoid, fusiform or cylindric with tapering tip.

Key to the Indian species of Amorphophallus sect. Conophallus
1. Leaves bulbiliferous, epiphyllar bulbils produced at junction of petiole with rachises and at axils of branches of rachises; spadix ovoid, or elongate obpyriform, creamcoloured.

A. carnosus -
Spathe with or without a constriction between basal tube and limb, c. 14-25 cm long with distinct blotches outside; spadix stipitate.4 4. Petiole and peduncle dark green with light greenish blotches and minute greenish white mottles in between blotches; leaflet-margin green; spathe with distinct constriction between tube and limb.
A. oncophyllus -Petiole and peduncle pinkish green to brownish green with cream to white irregular vertical linear stripes; leaflet-margins light pinkish; spathe without constriction between tube and limb.
A. bulbifer 5. Tuber cylindrical in reproductive phase, small and obconic in vegetative phase; petiole and peduncle turgid and brittle; peduncle 21-31 cm long; spathe 10.6-12.0cm long, greenish brown to greenish purple with light green mottles and dark purple spots outside; greenish yellow and smooth within, sometimes very light pinkish green tinged with purple spots at base within.
Notes: Amorphophallus bognerianus is related to A. bulbifer (Sims) Blume, but differs in having the inflorescence with short peduncle and erect fornicate spathe-limb.It also differs from A. bulbifer in having a different mottling of petiole and peduncle, and spadix shorter than spathe and spadix-appendix, more or less equals to the length of fertile portion of spadix in contrast to the condition in A. bulbifer where the spadix-appendix is longer than the length of the fertile portion of spadix.

Amorphophallus bulbifer (Sims) Blume
Phenology: Flowering: May-June; Fruiting: July-November.Notes: A. bulbifer closely resembles A. bognerianus but the latter differs by having the inflorescence with short peduncle, erect fornicate spathe limb and spadix shorter than spathe.It resembles A. oncophyllus, but differs in having different colour and pattern of mottling of petiole and peduncle, and erect limb of spathe without any constriction between the basal convolute tubular portion and the upper expanded limb.In A. oncophyllus the mature inflorescence is with a deflexed spathe-limb in contrast to the erect limb of A. bulbifer.
Notes: Amorphophallus carnosus, a little known rare and endemic species, has been rediscovered from Andaman after it was first collected by Prain's collector in the year 1899 and no later collections were available from the islands (Srivastava and Rao, 1993).After over 100 years, during May 1999 the species was rediscovered and collected both in flowering and vegetative stages from its type locality -Andaman islands and the rediscovery was reported by Sivadasan and Jaleel (2000a). A. carnosus is quite remarkable in having large-sized plants and inflorescence with erect spathe of about 39.5 cm long with prominent pale green colour outside and purplish orange at base, and reddish pink above within.It resembles A. oncophyllus, but differs in its large size, erect spathe, male zone about half the length of the female zone and an elongate obpyriform spadix-appendix with narrow tapered tip.
Distribution: So far known to occur only in Andaman Islands, India.Tubers sub-spherical, smooth, often produce short cylindric offsets, skin smooth.Petiole pale green to pale brownish with numerous elongate to irregular brown to dark brown spots; basal portion of rachises naked without decurrent bases of leaflets.Leaflets elliptic, elongate-elliptic or more or less oblong, upper leaflets with base long decurrent on rachis, apex acuminate.Inflorescence long or short peduncled; peduncle resembles petiole in colour and pattern of mottling.Spathe erect, ovate-oblong or narrowly elongate-triangular, acute or acuminate, with or without a shallow constriction between tube and limb, purplish or brownish green or pale yellowish brown outside, inner side verrucose or with rounded bumps and with or without unicellular silvery hairs at base.Spadix usually longer than spathe, sessile or stipitate.
Notes: Amorphophallus commutatus var.anmodensis resembles var.wayanadensis in general appearance of spathe and spadix, but differs by having a short peduncle of c. 8-10 cm long, male zone cylindrical and less than twice the length of the female zone, and the spathe-tube slightly purplish and verrucose with unicellular hairs at base within.
Distribution: A narrow endemic known to occur only in Anmod Ghat, Goa in India.
Notes: Amorphophallus commutatus var.commutatus resembles the other two varieties, viz. A. commutatus var.anmodensis and var.wayanadensis in general appearance of the spathe and spadix.But it differs from the above two in having a cylindric basal tube of spathe without constriction between tube and limb, spadix with male zone obconical, more than twice or more or less thrice the length of female zone, and female flowers with purplish colour at upper portion of ovary.
Notes: Amorphophallus commutatus var.wayanadensis reselmbes var.anmodensis in its general appearance of the spathe and spadix.But it is distinct in having a long peduncle of about 75-95 cm, tube of spathe yellowish with slight purplish colour at base with warts or verrucae and absence of unicellular silvery hairs within.

Amorphophallus nicolsonianus
Distribution: So far known to occur only in Kerala state in India.