148 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 3 



rotundatis, aliquando in regione segmentorum inferiorum et stipitum superiorura 

 prolificantibus, plus minusve 100 |.i crassis; cellulis medullaribus 2-3 stratosis, 

 cellulis corticalibus parvis, plus minusve 2 stratosis; tetrasporangiis in lobis curtis 

 ultimis abrupte expansis 2-plo latioribus quam segmentis et soros rotundatos for- 

 mantibus, lobis fertilibus plus minusve 200 n crassis, stratis corticalibus per 

 divisiones accessorias irregularesque in nematheciis transformatis ; tetrasporangiis 

 cruciatis; cystocarpiis nondum visis. 



Fronds from a simple disk attachment with almost no stolon develop- 

 ment, 20-25 cm. high, from a slender, compressed, branched stipe which 

 reaches 10-15 cm. before expanding to the blades; segments mostly 3 mm. 

 broad, the ultimate ones 1-2% cm. long with angles of between 30 and 45 

 degrees, with rounded apices, somewhat proliferous in region of lower 

 segments and upper stipes, about 100 |i thick, of 2-3 layers of medullary 

 cells covered by about 2 layers of small cortical cells ; tetraspores in 

 rounded sori at apices of the ultimate segments, each sharply expanded 

 into a short lobe at least twice as broad as the segment, this lobe about 

 200 n thick and showing considerably modified cortices in which accessory 

 and irregular cell divisions convert them into nemathecioid layers con- 

 taining the cruciate tetraspores ; cystocarps unknown. 



Type. — Cast ashore. Pebble Beach, Carmel Bay, Calif., Jan., 1917, 

 N. L. Gardner 3612; Herb. Univ. Calif. 372025. 



Extensively branched stipes, thin fronds, and narrow angles of the 

 dichotomies distinguish this species from other Rhodymenia species of the 

 North Pacific coasts. Its nearest relative may be R. arborescens, from 

 which it is distinguished by its thinner blades, longer, more slender stipe, 

 and less abundant segmentation of the upper fronds. 



(44) RHODYMENIA CORALLINA (Bory) Grev., Alg. Brit. 

 (1830), p. xlviii; Sphaerococcus corallinus Bory, Voy. Coquille, 

 Atlas (1826), tab. 16. 



Plate 21, Fig. 28 ; Plate 29, Fig. 42 



Bory's original figure shows a large, erect-appearing plant with a 

 branched, terete stipe, the blades from this stipe being themselves individ- 

 ually short stipitate. Moreover, he indicates an extended, abundantly 

 dichotomous blade with long segments divided by narrow angles. Agree- 

 ment with these points is found in specimens of three collections from the 

 region of South America in which this species was first found. The only 

 point of confusion remaining is in Bory's portrayal of the holdfast. He 

 does not indicate the presence of branched stolons around the holdfast, 

 but we may assume that his specimen either did not have a really complete 



