No abstract

No abstract

No abstract

No abstract

No abstract

s m i t h s o n i a n c o n t r i b u t i o n s t o b o t a n y • n u m b e r 1 0 6 SERIES PUBLICATIONS OF THE SMITHSONIAN INSTITUTIONEmphasis upon publication as a means of "diffusing knowledge" was expressed by the first Secretary of the Smithsonian. In his formal plan for the Institution, Joseph Henry outlined a program that included the following statement: "It is proposed to publish a series of reports, giving an account of the new discoveries in science, and of the changes made from year to year in all branches of knowledge." This theme of basic research has been adhered to through the years by thousands of titles issued in series publications under the Smithsonian imprint, commencing with Smithsonian Contributions to Knowledge in 1848 and continuing with the following active series: s m i t h s o n i a n c o n t r i b u t i o n s t o b o t a n y • n u m b e r 1 0 6

Infrared analyses of the carrageenan in ten species (representing four genera) of Gigartinaceae and one species of Hypneaceae in different reproductive phases from the northwestern coast of Baja California were studied . Cystocarpic samples of the Gigartinaceae presented varying degrees of a 1c/i`hybrid' . The degree of hybridization was determined based on the ratio between the peak absorbances at 805/845 cm -' . A high correlation was observed between the 805/845 cm -' and 805/970 cm -' ratios . Tetrasporic samples of Gigartina leptorhynchos, Iridaea splendens, Rhodoglossum affine and R . roseum, presented a ,,-carrageenan profile, whereas Gigartina tepida, G . exasperata, G . harveyana, G . canaliculata and G . spinosa presented a c-carrageenan . The tetrasporic sample of Hypnea valentiae showed a ic-carrageenan with a very low degree of hybridization .

Kjellman (Ulvales, Chlorophyta) was recorded for the first time for the Pacific coast of Mexico. An alga native to Asia, U. pertusa has just recently been recorded in the southern coast of California (USA). The identification of U. pertusa was based on the observation of the morphology and reproductive characters of the collected specimens. Furthermore, the species identity was confirmed by molecular comparison between nuclearencoded ITS2 sequences of the Mexican samples and those of other Ulva species in GenBnak data. Habitat and distribution of U. pertusa along the Pacific coast of North America are also described. Considering our new report of its occurrence in Mexico, we conclude that U. pertusa is expanding its geographical distribution by trans-ocean introductions.