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ALLAN HANCOCK PACIFIC EXPEDITIONS 



VOL. 12 



Text Figure 3. Polystphonia Hoiuei. The apical portion of a creep- 

 ing axis showing the ascending tip, with one erect branch and several 

 less well developed. Drawn by G. J. Hollenberg. x 195. 



Polysiphonia Howei Hollenberg n. sp.^^^^ 

 Text Figure 3 



Polysiphonia Howei Hollenberg sp. nov. Plants diminutive, creeping, 

 densely matted, and forming patches several centimeters in diameter; 

 prostrate branches 100-170 ju, in diameter, composed of segments mostly 

 about as long as broad or shorter, and attached by frequent unicellular 

 rhizoids, arising one to several per segment at the distal ends of the peri- 

 central cells, from which they are cut oH by crosswalk ; pericentral cells 

 10-12; branches arising exogenously on all sides and at irregular intervals 

 but mostly either two or four segments apart from the tips of the prostrate 

 branches, spiraling more or less to the right as viewed from the branch 

 tip, the ventral and often the lateral branches either remaining undevel- 



191b Polysiphonia Howei Hollenberg n. sp. — Plantae parvissimae repentes inter- 

 textae; ramis procumbentibus 100-170 ij- diam., a rhizoideis adfixis ad apices 

 terminalea circumcentralium cellularum ex segmentis omnibus; cellulis circum- 

 centralibus 10-12; ramis exogenis radiantibus sed inferioribus etiamque saepe 

 lateralibus deficientibus vel in ramos novos repentes transformatis; subsimplicibus 

 erectis ramis primum arcuatis, 2-3 mm altis, raro 5 mm, 70-150 \i diam.; tricho- 

 blastis ad apices ramorum numerosis, demum deciduis; tetrasporangiis singulis in 

 serie longa, 40-55 \i diam.; reproductio sexualis ignoto. Planta typica in loco dicto 

 Whale Cay, Berry Is., Bahamas, legit M. A. Howe no. 3478, Jan. 29, 1905, in herb. 

 New York Botanical Garden. 



