Ceratophyllum platyacanthum subsp . oryzetorum ( Kom . ) Les ( Ceratophyllaceae ) : an addition to the flora of India from Kashmir Himalaya

Ceratophyllum platyacanthum Cham. subsp. oryzetorum (Kom.) Les (Ceratophyllaceae) is recorded for the first time from Kashmir Himalaya and India. The species differs from its closely related taxon, Ceratophyllum demersum, in having smaller leaves and the fruit with a facial spine. A comparison between Ceratophyllum demersum and C. platyacanthum subsp. oryzetorum, and the taxonomic description, photographs and distribution map are provided to facilitate its field identification in the region.

The earliest record of Ceratophyllum from the Indian subcontinent was established by Hooker (1885),who reported a single species: C. demersum L. Cook (1996) later recorded two species from India: C. demersum (which occurs throughout India), and C. muricatum (which is known only from the south and central Indian states of Kerala, Madhya Pradesh, Odhisa, Rajasthan, and Tamil Nadu).Until now, only C. demersum has been recorded from freshwater ecosystems in the Kashmir Himalaya region, which is located along the northwestern boundary of India (Kaul and Zutshi 1967;Stewart, 1972;Kak and Durani 1985;Kak, 1990).
While carrying out botanical surveys to document the aquatic flora of the Kashmir Himalaya, specimens of a typical Ceratophyllum species were collected from Manasbal Lake (1,590 m above sea level [a.s.l.]; 34°15′26″ N, 074°41′26″ E) and the Hokersar wetland area (1,600 m a.s.l.; 34°06′29″ N, 074°43′39″ E).A critical examination of morphological features, in particular the mature fruit characters (Les 1988b), readily identified these specimens as C. platyacanthum subsp.oryzetorum (V.Komarov) Les, a taxon not reported previously from the region in the previously published taxonomic literature (Hooker 1885;Kaul and Zutshi 1967;Stewart 1972;Kak 1990;Cook 1996).However, in an unpublished account, Les (1986) earlier had confirmed the presence of C. platyacanthum subsp.oryzetorum in Kashmir based on a specimen from Dal Lake that was collected in 1917.Our eventual search of herbarium material at Missouri Botanical Garden (MO), Philadelphia Herbarium (PHIL), and University of Kashmir Herbarium (KASH) turned up additional records, which were unknown previously because of their misidentification as C. demersum.Therefore, the current report is to document the occurrence and clarify the distribution of C. platyacanthum subsp.oryzetorum in the Kashmir Himalaya, India.
The Kashmir Himalaya is situated in the northern fringe of the India between 33°22′ and 34°50′ N and 073°55′ and 073°33′ E (Figure 1), covering an area of ca.16,000 km 2 .Standard herbarium methods (Bridson and Forman 1992) were used during collection, processing and preparation of the herbarium specimens.New voucher specimens have been deposited at the University of Kashmir Herbarium (KASH); previously collected specimens were located at MO and PHIL.The micro-characters were analyzed and photographed using a trinocular stereo zoom microscope (Model: Carl Zeiss Discovery V8). and several comparisons are provided to facilitate their taxonomic identification (Figure 2; Table 1).
Global distribution: China, Japan, Korean Peninsula, Russia (Far East) and now reported from the India (Kashmir Himalaya) Local distribution: This plant has now been recorded from three districts in the Kashmir Himalaya including Srinagar (Dal lake, Hokersar wetland), Ganderbal (Manasbal), and Anantnag (Dialgam) (Figure 1).
Specimens examined (numbers in brackets refer to Figure 1): India.Jammu and Kashmir.Anantnag District (4): Dialgam, 1,700 m a.s.l., 21-VII-1975, A.M. Kak,3429 (KASH).Ganderbal District ( 1 Hooker ( 1885) recorded only C. demersum L. from India and Ceylon (now Sri Lanka), and was unable to distinguish any potentially different species due to the absence of live material.Nearly a century later, Les (1986) discovered a specimen of C. platyacanthum subsp.oryzetorum that was collected from Dal Lake, Kashmir in 1917 (Stewart, s.n.; MO).Although that record (and another from the same locality: Stewart 7163; PHIL) represent the earliest known collections of C. platyacanthum subsp.oryzetorum from India, those reports were never published.An additional unpublished record from Dal Lake (collected in 1972) also was discovered by the authors among several misidentified Ceratophyllum specimens at KASH.Subsequently, a new locality for this taxon was found at Dialgam from a specimen collected in 1975 (A.M.Kak,3429), which again was correctly determined among the misidentified material at KASH.No other records of this taxon materialized until 2013, when several collections were made by the authors at Manasbal Lake (Figure 1).
In addition to C. platyacanthum, Les (1986) also reported the occurrence of C. muricatum in India, a record that had remained unpublished until the species was included in a contemporary aquatic flora of the country (Cook 1996).
Yet, that flora lacked any mention of C. platyacanthum, which is first documented by the present account.Therefore, based on the present study, the flora of the India currently includes three taxa: C. demersum, C. muricatum, and C. platyacanthum subsp.oryzetorum.Only C. demersum and C. platyacanthum subsp.oryzetorum are known to occur in the Kashmir Himalaya,