EvANS: REPORT ON THE HEPATICAE OF ALASKA 597 
and Holt in 1885. It was found a second time at Slievemore, 
Achill Island, off the western coast of Ireland, by Jones and Duncan 
in 1911. No other stations have been reported. Through the 
kindness of Miss Haynes the writer has been enabled to compare 
material from both Irish stations with the specimens from Alaska, 
and finds that they agree in all essential respects. In No. 109 
the species grew mixed with Herberta adunca. 
In size and general habit B. Pearsoni bears a strong resemblance 
to the typical forms of B. tricrenata. The leaves, especially when 
dry, are umbricated and strongly decurved in both species, while 
the apex is usually bi- or tridentate with variable teeth. The 
distinctive characters of B. Pearsoni are the following: the strongly 
dilated antical portion of the leaves, the lack of distinct teeth on 
the underleaves, the very large trigones in the cells of both leaves 
and underleaves. The antical portion is so strongly dilated that 
it makes the leaf arch considerably beyond the axis and forms a 
cordate expansion at the base. The trigones in typical cases are 
separated by narrow pits with straight sides, the cell-cavities 
being distinctly stellate; the sides of the trigones are strongly 
convex or truncate, and coalescence of trigones is not infrequent. 
The middle lamellae are very distinct. The underleaves are 
contiguous to imbricated and are rounded or subcordate at the 
base; in outline they vary from orbicular to broadly ovate, the 
lateral margins are somewhat outwardly curved and are often 
reflexed at the base, and the apex is truncate or slightly retuse. 
Full descriptions of B. Pearsoni, with figures, may be found in 
Pearson’s Hepaticae of the British Isles (p. 133, pl. 50) and in 
Macvicar’s Student’s Handbook of British Hepatics (p. 319, 
I-4). 
Among exotic species which are allied to B. Pearsoni, the 
Hawaiian B. Didericiana (Gottsche) Steph.* may be particularly 
noted. In this species, which is about as large as B. Pearsont, the 
leaves are much less convex and are also less dilated in the antical 
Portion, while the underleaves are almost constantly toothed at 
the truncate apex, the teeth Le. very variable. The leaves 
* See ¢ CM, | Sonics Jr. Trans. Connecticut Acad. 12: 15. pl. 4 f. I-13. 
In his Species Hepaticarum (Bull. Herb. Boissier Il. 8: 775- font aes vi 
Changed the name of this species to Mastigobryum Didrichsenii. 
