Stenogramme interrupta, (C. Ag.) Montg. 
BY 
T. JOHNSON, D.Sc., F.L.S., 
Professor of Botany in the Royal College of Science, Dublin. 
With Plate XXIII. 
HE genus Stenogramme [stems, narrow, gramme , line) 
- 1 - was founded by Harvey in 1841 to include a Californian 
sea-weed, in which the fruit had the anomalous form of a 
nerve-like, or midrib-like, interrupted line in the thallus- 
segments. Of the two species of Stenogramme , S. interrupta , 
(C. Ag.) Montg., and 5 . leptophylla , J. Ag., A. interrupta , 
though a rare British red alga \ is to be found growing in 
Plymouth waters, and may be obtained, in all stages, in 
tolerable plenty by dredging in 5-7 fathoms in Plymouth 
Sound, west of the Duke Rock buoy. In spite of the unusual 
form and position of the cystocarps, the female plants have 
not been described since Harvey examined the ripe fruits ; 
the male plants, beyond a passing reference in the Etudes 
Phycologiques 2 , have not been described ; and doubts still 
exist as to the characters of the tetrasporangiate plants. 
Tetrasporangiate Plant . 
The tetraspores are cruciate (Fig. 2): the tetrasporangia are 
so arranged as to form wart-like sori of varying size and out- 
line, irregularly scattered over both surfaces of the thallus 
1 Harvey, Phyc. Brit., PI. CLVII. 
2 Thuret et Bornet, Etudes Phycologiques, p. 82. 
[Annals of Botany, Vol. VI. No. XXIV, December 1892.] 
