Mexican Mosquito Fern [Azolla mexicana Presl.]

Mexican Mosquito Fern [Azolla mexicana Presl.]

Listing CNPS List 4 R-E-D Code 1-2-1

State/Federal. Status -- None SALVINIACEAE August

Global Rank G5 State Rank S3?

Distribution: San Diego County, Butte County, Kern County, Modoc County, Lake County, Nevada County, Plumas County, Tulare County, Santa Clara County; Arizona; Idaho; New Mexico; Nevada; Oregon; Texas; Utah; Washington; Wyoming; Baja California, Mexico; and Guatemala

Habitat: This is an aquatic species which floats on the surface of ponds.

Known Sites: No specific locales are known for San Diego County; although a non-specific report from the CNDDB files mentions this county.

Status: The present status of this species in San Diego County as well as elsewhere in Southern California is unknown; no verified herbarium specimens are found at the San Diego Natural History Museum. The related and regionally common Azolla filiculoides is apparently difficult to differentiate in the field from Mexican Duckweed. In Mexican Mosquito Fern the megaspore (i.e., a primitive seed) is pitted on the basal portion, and the glochidia are septate (i.e., divided into portions); both traits requiring a microscope to determine. More information is needed.

Copyright May 1994 Craig H. Reiser.

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