260 BOTANICAL GAZETTE [MARCH 
she has made three reports on her studies. The work has been carried on in 
Southern England, and careful effort was made to compare conditions in 
several different counties. It is concluded that some weeds are ubiquists, 
occurring on all soils, whereas other weeds are definitely symptomatic. Symp- 
tomatic species are most in evidence on chalk, although it is to be noted that 
most of the weeds which are calcifuges in Bedfordshire are calcicoles in Wilt- 
shire and Somerset. Examples of such reversal are Chenopodium album and 
Bartsia Odontites; Poa annua is about the only consistent calcifuge observed. 
In one place a mingling of chalk plants and “acid plants” was explained by a 
non-calcareous surface soil overlying a chalk subsoil. In some cases the char- 
acter of the crop influences the weed population, as in certain leguminous seed 
crops. Some plants, as the mayweeds (Anthemis, Matricaria), are impatient 
of competition.—H. C. Cow tes. 
Morphology of Macroglossum. —Macroglossum is a new generic type of the 
Marattiaceae described in 1909 by CopeLAND from material obtained from 
Borneo. recent visit to this region enabled CAMPBELL to secure material 
of this fern, and he has now published an account of its structure and affinities.” 
The genus now comprises two species, the second one having been found grow- 
ing in the botanical gardens at Buitenzorg, but of unknown origin. The 
species studied is a large plant, the leaves reaching sometimes a length of 
4meters. It belongs to the Angiopteris group, related apparently most nearly 
to Archangiopteris. It differs much in general appearance from Angiopierts, 
as well as in its much elongated and partially immersed sori. The sporangia 
also are smaller and very much more numerous than those of Angiopieris. 
The gametophyte may reach a length of 3 cm., and branching is not uncommon. 
The antheridia occur on both surfaces, and the number of sperm mother cells 
is probably greater than in any other of the Marattiaceae. The embryo 
evelops a conspicuous suspensor, as in Danaea. The author also describes 
certain anatomical details, comparing them with those of the other Marattia- 
ceae.—J. M._C. 
Leaf- she ath trichomes in grasses.—In many grasses, especially those of 
eat: and alpine habitats, the leaf sheaths do not decay immediately 
after death. Instead of this they remain, forming a sort of mantle about the 
young sheaths. That this feature is especially characteristic of xerophytic 
grasses was noted in 1890 by HAcKEL, who regarded the mantles as having 4 
protective function, tending to reduce transpiration. H. BROCKMANN-JEROSCH™ 
Bunion. WintFrep E., The weeds of arable — in relation to the soils on 
which they grow. Ann. Botany 25:155-165. 1911; 26:95—-I09. 1912; 27: 141-166. 
Igt3 
a 2 Casi ELL, D. H., The structure and affinities ae a acroglossum Alidae Cope- 
land. Ann. Botany 28: 651-669. pls. 46-48. figs. 8. 
™ BROCKMANN-JEROSCH, H., Die Trichome der eH bei Griisern. Ber- 
Deutsch. Bot. Gesells. 31: 590-504. pl. r. 1914 
