Hydrilla verticillata (Hydrocharitaceae) in Connecticut

A specimen of hydrilla (Hydrilla verticillata (L.f.) Royle) collected at Mystic, Connecticut in 1989 was recently discovered in the University of Connecticut herbarium. Unnoticed previously because of its misidentification as egeria (Egeria densa Planch.), this specimen is the first authenticated re...

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Bibliographic Details
Published in:Journal of aquatic plant management 1997-01, Vol.35, p.10-14
Main Authors: Les, D H, Mehrhoff, L J, Cleland, MA, Gabel, J D
Format: Article
Language:English
Subjects:
Freshwater
Hydrilla verticillata
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Summary:A specimen of hydrilla (Hydrilla verticillata (L.f.) Royle) collected at Mystic, Connecticut in 1989 was recently discovered in the University of Connecticut herbarium. Unnoticed previously because of its misidentification as egeria (Egeria densa Planch.), this specimen is the first authenticated record of hydrilla in New England, and represents the most northern locality of the species currently known in eastern North America. A 1996 field survey verified that hydrilla continues to thrive at the Connecticut site. Connecticut plants were positively identified as hydrilla by morphological features, and by comparing the rbcL gene sequence of Connecticut specimens with a hydrilla plant from India. Internode lengths of Connecticut hydrilla exceeded those reported for both dioecious and monoecious strains grown in greenhouse conditions. However, leaf lengths of Connecticut hydrilla were comparable to those of the dioecious strain designated as 'USA hydrilla I'. A RAPD profile of Connecticut hydrilla produced the molecular marker that reportedly distinguishes the dioecious strain. Cytological analysis indicated that the Connecticut hydrilla plants are triploid (2n = 3x = 24). Hydrilla in Connecticut presumably represents an introduction of dioecious plants. Hydrilla grew well on both sandy and mucky substrates and apparently overwinters in Connecticut by production of numerous, subterranean stem tubers.
ISSN:0146-6623