MACROCYSTIS 63 
of the upper blades obscurely denticulate, crenulate, or entire; 
muciferous canals and parenchyma cells as in 09166; the vesicles 
are long-ellipsoid, clavate-ellipsoid, clavate-pyriform, or subpyri- 
form, mostly 1.5-4 cm. X 0.8-1.5 cm., 114-4 times as long as 
their greatest width; the sori, so far as observed, are confined to 
опе or two compound basal blades (PLATE 21). The lowest of 
these blades are destitute of vesicles; some of the higher may be 
provided with them; the compound blade usually consists of four 
bladelets or sporophyls, but two and three occur, especially very 
close to the base of the plant; the sori occur on both sides of the 
sporophyl and form large blotches or cover continuously a large 
part of the surface of the sporophyl. 
Macrocystis has been generally supposed to be an inhabitant 
of 2-30 meters of water (low tide). Hooker and Harvey* say of 
it that “One thing alone it requires, and that is, a mean depth 
of six or more fathoms.” Setchell} refers to its occurrence on the 
Pacific coast of North America in “20 to 30 meters depth of water.” 
McFarlandt states that “it grows on rocks off the coast in from 5 
to 15 fathoms of water, generally." Crandall,§ however, has 
observed it off the southern coast of California in “2% fathoms,” 
though the holdfast is there attached “ағ a depth of, usually 4 to 
то fathoms.” But the shallowest water from which Macrocystis 
has hitherto been actually recorded seems to be at Moss Beach, 
San Mateo Co., California, where Setchell, according to Hoffman, || 
collected fertile specimens growing where “very nearly uncovered 
at the lowest tide.” 
PLATE 18, FIGURE B. Macrocystis inteprifolia 
A photograph, taken on the Chincha Islands by Dr. Coker, showing this kelp in 
situ, near the low-tide line. 
PLATE 19. Macrocystis integrifolia 
A photograph, showing massively interwoven rhizomes and hapteres, etc., 
natural size, (Coker 09614, from material preserved in liqui id). 
# In Suspe J. D. Flora Antarctica 461. 1846 
fSetchell, W. A. Тһе kelps of the United Slates and Alaska, in Fertilizer 
resources of ы United States, си Document Хо. 190, 62d Congress, р. 159. 
1012. 
+ McFarland, Е. М. Тһе kelps of the central Californian coast. Loc. cit. 200. 
$ Crandall, W. С. The kelps of the southern Californian coast. Loc. cit. 211. 
|| Hoffman, E. J. Fructification of M. acrocystis. Univ. В сам Publ. Bot. 4: 
154. 1911 
