Aponogetons of Indo-Asia

Described in 1968 by HWE Van Bruggen. Found in Eastern and Western coastal India in fresh or brackish water; found at depths up to 1.5 to 3M, with depths 1M greater during high tide.

bruggenii

Growing in rice fields on Tacarli River at Nerurpar-Dhamapur (16 � -0 '41''N, 73 � -37 `30 `` east longitude), 15-20 m above sea level, so far, this type location is the only location it's known from.

The annual rainfall there is 200-225 mm drop, mostly from June to September in the summer rainy season. The water all but dries up in the dry season.

crispus

red

seedlings

Probably the most common Aponogeton in culture, known to science since 1791, this plant is found in Sri Lanka and South India.

jacobsenii

Threatened in its native Sri Lanka on the coastal wetlands.

lakhonensis

loriae

Discovered in 1897, similar to A. elongatus, but found only in New Guinea. Rare in both aquaria and nature, not a terribly robust species.

natans

nateshii

Described in 2017 by Yadav et al. Found so far in only three ponds a good distance apart. In Rajapur, Surla / Chorla and Dhargal the shape, size and proportions of the leaf are different, even the creeping rhizome (not a "tuber") is different. See the Table 1

rigidifolius

Leaves are quite leathery as the name suggests.

robinsonii

Josef Bogner stated in an Aqua Planta article that A. robinsonii plants, only developing long submerged but not true floating leaves, represent another closely related species, A. eberhardtii.

satarensis

Found in India.

stachyosporus

Note the tiny plantlet at the end of what would otherwise be an inflorescence.

undulatus

wolfgangianus

New in 2016!

Notes

1) A. stachyosporus and A. undulatus

A. stachyosporus and A. undulatus were held to be synonyms, but, Les, Moody and Jacobs (2005) state:

Bruggen (1985) treated A. undulatus and the narrower-leaved A. stachyosporus as conspecific, assuming that wide variability of leaf morphology existed in A. undulatus. This conclusion would be supported by our cpDNA sequences, which were identical in the two taxa (Fig. 4); however, we found their ITS sequences to differ by seven substitutions (Fig. 3), a level comparable to (or exceeding) the degree of ITS divergence that we observed between a number of other Aponogeton species. The ITS data would indicate that the distinctness of these two taxa should be reconsidered.

Given that there are lessor differences between other different species of Aponogeton it would seem prudent to refer to A. stachysporus and A. undulatus are different species.

2) With the publication in 2016 of A. wolfganensis there is a new key to Indian species of Aponogeton

Key to the species of Aponogeton from India
Key to the Indian species of Aponogeton based on number of seeds per fruit and embryo characters is provided below and the morphological features of embryo of Indian species of Aponogeton and A. jacobsenii from Sri Lanka are depicted in Table 2 and shown in Fig. 3.

1. Seeds 4�8 per fruit, embryo elliptic, small, 3�4 � 2�2.5 mm ...................... 2
� Seeds 1�2 per fruit, embryo elliptic or globose or trapezoid, large ............... 3
2. Embryo 3 � 2 mm .................................................................. A. lakhonensis
� Embryo 4 � 2.5 mm ................................................................. A. natans
3. Embryo without appendages ........................................................ 4
� Embryo with appendages ............................................................ 8
4. Plumule attached at side of the embryo at the middle ............................. A. wolfgangianus
� Plumule attached at side of the embryo at the base ................................ 5
5. Embryo elliptic, cotyledon non-grooved, pointed .................................. A. bruggenii
� Embryo elliptic, grooved, rounded ................................................. 6
6. Embryo elliptic, cotyledon with narrow dorsal grove .............................. A. satarensis
� Embryo elliptic, cotyledon with broad concave groove .............................. 7
7. Embryo 10�12 � 4�5 mm ............................................................ A. crispus
� Embryo 5 � 2 mm ................................................................... A. undulatus
8. Embryo obovate, tuberous, crowned with 3�4 tortuous appendage .................... A. appendiculatus
� Embryo globular, tuberous, 16�20 (5�6) appendages all around ...................... A. nateshii