Aquatic and wetland plant communities are some of the most important communities worldwide. Yet recognition of the aquatic and wetland environments as critical ecosystems has been slow to emerge, and a better understanding of aquatic organisms is greatly needed. Field studies are critical in developing a full understanding of floristic affinities or of characteristics of any group of plants. Field studies allow for the examination of population and community level structures, ecological relationships, morphological variation and distributional patterns. Thus, field observations in distant regions allow for a greater insight and interpretation of the biology of aquatic and wetland plants.

During the summers of 1993 and 1994 reciprocal exchange expeditions, coordinated through the official USA-RUSSIA Botanical Exchange Program, USFWS/Interior Department Office of International Affairs were organized by Dr. Garrett E. Crow, University of New Hampshire, and Dr. Ivan Krasnoborov, Central Siberian Botanical Garden, Novosibirsk. A 15-year collaborative effort by G. Crow and C. B. Hellquist has focused on taxonomic and floristic research on the aquatic flora of northeastern North America and the Siberians have also been actively involved in research on the aquatic flora of their region. Aquatic plants communities are particularly well developed in New England and Siberia. Floristic similarities between Siberia and New England are incredibly striking and the aquatic flora has strong phytogeographical affinities. The exchange program is an important opportunity to jointly gather valuable data which will contribute to a better understanding of the biogeography, taxonomy and systematics of specific aquatic plant groups.

A 5-week botanical expedition in south-central Siberia, Russia took place during the summer of 1993. The American team consisted of Dr. Garrett E. Crow, expedition leader (University of New Hampshire), Dr. C. Barre Hellquist (North Adams State College), Dr. C. Thomas Philbrick (Rancho Santa Ana Botanic Garden), and Donald J. Padgett (Graduate Research Assistant, University of New Hampshire). The expedition, led by Dr. Ivan Krasnoborov (Central Siberian Botanical Garden) and Dr. Pavel Volobaev (Kemerovo State University) involved 1 week of field work in the Novosibirsk region, 3 weeks in the Kemerovo/Khakass region. and 2 weeks in the Altai region (see attached map).

In all, fifty collection sites were visited. Approximately 1900 herbarium specimens were collected. Additionally about 100 samples were prepared for DNA analysis of the genera Nuphar (Yellow Waterlily), Callitriche (Water Starwort), and Utricularia (Bladderwort). Live plant specimens were collected for cultivation at the University for research purposes of the following species: Nuphar pumila, Nuphar lutea, Nymphaea candida, and Nymphaea tetragona.

The most frequently encountered group of aquatic plants was the genus Potomogeton (Pondweeds). This was particularly welcome as both Drs. Hellquist (USA) and Volobaev (Russia) have expertise in the taxonomy of this difficult genus. Eighteen species of Potamogeton were collected, representing 77 populations. Ten of these species are native to both Siberia and New England; one of the Eurasian species (Potamogeton crispus) is also adventive in New England; and 7 species are closely related to New England species. As a result of field observations on these populations, it has become clear to us that Potamogeton pectinatus complex (including P. chakassiensis, P. macrocarpus, P. hingii and several varieties of P. pectinatus) represents a group whose taxonomy is very much in need of further study. A collaborative effort with the Russians would be very beneficial in understanding this complex group.

Donald Padgett is conducting a monographic study of the genus Nuphar (Yellow Water-lilies) for this doctoral dissertation (under the direction of Dr. Crow). The trip provided an important opportunity to study in situ the two Asian species in Siberia, Nuphar pumila and N. lutea. The latter species is closely related to our N. variegata, and, in fact, has been included in the same species by some authors. However, the field observations allowed us to note important morphological differences. The other species is a very small Yellow Water-lily, very similar to one we have in New England. Some authors have regarded our New England plants to be conspecific with the species in Siberia. Again, the field studies we conducted allow us to make important comparisons and note differences in our plants. Additionally, live plants from Siberia are now being grown in the greenhouses at the University of New Hampshire for further comparative studies.

Another water-lily of particular interest to us is Nymphaea tetragona (Dwarf White Water-lily). This plant is on the Maine and the New England regional endangered species lists. It has long been considered conspecific with the Asian species. Field observations were instrumental in our recognizing the North American plants as a distinct species, Nymphaea leibergii, for our book Aquatic and Wetland Plants of Northeastern North America (Crow and Hellquist, in press). Our collections have also been available to Dr. John Wiersema, the botanist writing the taxonomic treatment of Nymphaea for Flora of North America. He is in agreement with our viewpoint that the two should be regarded as distinct species.

Several other collections were also noteworthy. Myriophyllum exalbescens, widespread in North America, was recently determined to be conspecific with M. sibiricum, and since the latter name was published first, that scientific name has nomenclatural priority. It was very helpful for us to see M. sibiricum in Siberia--it was fairly common, although few specimens from Siberia exist in North American herbaria.

Utricularia vulgaris (Common Bladderwort) of Eurasian has recently been treated as distinct from the North America U. vulgaris (as U. macrorhiza). It has been my contention that the two are not distinct species. Field observations in Siberia have reinforced my viewpoint.

We were surprised to find that Hydrilla verticillata, listed by the USDA as a noxious weed, is quite hardy in Siberia. Introductions of this species into the southeastern United States are tropical in origin, and as a result are weedy only in the southeast (with only occasional sites occurring northward to Delaware). It would be devastating for a cold-hardy race to become established in our northern aquatic habitats.

Another weedy group is the genus Salvinia. Several have been very problematic in the tropics and in warm waters of the southeastern U.S. Salvinia natans was collected in Siberia. An infestation of this in the colder regions of the U.S. would have unwelcome consequences.

One further aquatic weed of concern is Trapa natans, a species that forms large floating mats of vegetation. There are several infestations in the northeastern U.S. and considerable monies have been spent to control this noxious weed. We collected herbarium material of Trapa pectinata, which to our eyes did not really differ from Trapa natans. It is quite hardy in cold climes.

It was also interesting to see several other aquatic weeds which have become established in the U.S. growing in their native Siberian habitats--quite in balance with other aquatic vegetation. These included Nymphoides peltata (Yellow Floating-heart), Lythrum salicaria (Purple Loosestrife), and Butomus umbellatus (Flowering Rush).

During the summer of 1994 the American team hosted the Russian team for a 5-week expedition in New England. The Russian scientists participating in the exchange included Dr. Ivan Krasnoborov, team leader (Vice-director, Central Siberian Botanical Garden), Dr. Igor Koropachinski (Director, Central Siberian Botanical Garden), Dr. Pavel Volobaev (Director of the Herbarium, Kemerovo State University), and Dr. Alexsandr Shmakov (Director of the Botanical Garden, Altai State University). Using the Hodgdon Herbarium, University of New Hampshire serving as a base of operations, field trips were conducted in New Hampshire, northern and western Vermont, northern Maine, Massachusetts, Rhode Island, and Connecticut (see attached map).

A total of 72 field sites were visited and approximately 1500 herbarium specimens were collected by the Russians. As was the case in Siberia, the genus Potamogeton (Pondweeds) was the most frequently encountered group of aquatic plants. We were able to show the Russians all 32 species of Potamogeton. New England probably has more species of Potamogeton than any other area in North America. This was especially valuable to Dr. Volobaev.

In addition to field work we were able to introduce the Russian team to research on aquatic plants involving molecular techniques. Although costs of molecular research would be prohibitive at the institutions in Siberia at the present time, it is important for the Russians to be aware of the research currently being done on aquatic plants using molecular approaches.

An outgrowth of the botanical exchange is the desire by both sides to continue to cooperate on botanical research. Preliminary discussions have already taken place to set up an exchange to look at further evolutionary/phytogeographical problems relative to the affinities of North American and Asian plants. We are particularly interested in field work in the Russian Far East relative to the evolutionary history of the wild strawberries, in order to better understand the genetics of cultivated strawberries.

The funding from the National Geographic Society has provided a very important opportunity for joint field work which has yielded valuable information regarding the biogeography, taxonomy, and systematics in a number of aquatic plant groups. Because of the strong floristic similarities between New England and Siberia, the results of this joint program has been of great benefit to both the Russian and American scientists.