rgry] - CURRENT LITERATURE 327 
covery is interesting, since it is the only record of a peptase occurring in plants 
unassociated with ereptase. The enzyme is present as such, not in the form 
of zymogen. The leaves of Drosera were found to be capable of absorbing 
_dissolved peptones from liquids placed on their surfaces in a few hours.— 
CHARLES A. SHULL 
Hepaticae in Scotland.—Macvicar* has published a full account of the 
liverworts of Scotland, stating that “this work may be regarded as a new 
departure for Scotland in this branch of botany,” previous publications 
having been fragmentary. An ecological discussion of nearly 50 pages pre- 
cedes the list, the latter including a full list of stations under each species. 
Among other interesting facts of distribution, the altitudes to which species 
ascend may be mentioned. Of the 225 species included in the list, 20 ascend 
above 4000 ft., 61 reach 3000-4000 ft., and 32 reach 2000-3000 [t.; which 
means that half of the Scottish species ascend above 2000 ft. There are 67 
genera recognized in the list, those including 10 or more species being Lophozia 
(26), Scappania (20), Marsupella (13), and Cephalozia (10).—J. M. C. 
A cretaceous Pityoxylon with ray tracheids.—It has been supposed that 
the occurrence of ray tracheids in the pinelike conifers is more recent than 
the Cretaceous, so that their discovery by BAILEY” in a Pityoxylon from the 
Upper Cretaceous of New Jersey is one of considerable interest. The species 
represents a structure intermediate between the older cretaceous pines and 
the most primitive of living pines; and the infrequent occurrence of ray 
tracheids in the older portions of the stems and their entire absence from 
the younger wood are taken to indicate that these structures are of recent 
origin and are not strongly fixed upon the plant. This shifts the develop- 
ment of ray tracheids from the Tertiary to the Upper Cretaceous.—J. M. C. 
Longevity of seeds.—Miss RreEs*® has made a study of the relation exist- 
ing between the structure and permeability of the coats and the longevity of 
seeds. In general, the macrobiotic seeds (retaining vitality for more than 15 
years) belong to the legumes and have highly cutinized coats. Eucalyptus calo- 
phylla and E. diversicolor are exceptions. They possess no impervious cover- 
ing, and, contrary to the general situation ag macrobiotic seeds, they are 
large and very rich in oils —Witt1am CROCKE 
boratory air.—Netyusow” has studied the growth of the pea seedling 
in in laboratory air and comes to the following conclusions: Ethylene is the 
© Macvicar, SyMERS M., The oe oe of Hepaticae in Scotland. Trans. 
and Proc. Bot, Soc. Edinburgh 25:vi+ 336. 
7 Bartey, I. W., : cretaceous pe a marginal tracheids. Ann. Botany 
25:315-325. pl. 26 
Rees, BERTHA, canes of seeds and nga and nature of the seed coat. 
Proc. Roy. Soe Victoria N.S. 23:393-414. 19 
* NELJUBow, D.., Geotropism in der isi Ber. Deutsch. Bot. 
Gesells. Sekar ck IQII. 
