286 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
study of the material from British Columbia and has no hesitation in referring 
it to A. lindenbergiana. 
Although Stephani’s description of the species mentions most of the more 
important characters, it is not altogether satisfactory. He says nothing, for 
example, about the characteristic spores and elaters, although Nees von Esen- 
beck had described them in his original account. Stephani likewise makes no 
allusion to branching by dichotomy, the usual method, stating that the thallus 
innovates at the apex or, more rarely, gives rise to ventral outgrowths, In his 
account of ’, commutata he makes similar statements about the branching and 
describes the spores as 68 » in diameter, yellowish brown, and with coarsely 
lobed wings, thus giving a somewhat misleading idea of their appearance. In 
all probability the capsules at his disposal, which he describes as subhyaline, 
were immature or abnormally developed. 
There is little danger of confusing A. lindenbergiana with A. saccata, although 
they have certain structural features in common. The thallus of A. linden- 
bergiana is considerably the larger of the two and lacks the apical cluster of 
hyaline scale appendages, which forms so characteristic a feature of the smaller 
species. The sharp keel, which is of course seen with especial clearness in 
cross sections, is a peculiarity which distinguishes the plant not only from A, 
saccata but from most other members of the genus, and the deep purple pseudo- 
perianths, spores, and elaters are likewise very distinctive, 
In the material from Mount Rainier a few ventral tubers were observed, 
similar to those described and figured by Karsten’ in the case of Conocephalum 
conicum (L.) Dum. They represent intercalary outgrowths from the side of 
the keel, which easily become detached, and are in the form of solid spherical 
or ellipsoidal masses of cells. Scattered over the surface, especially at the 
apical end, a few narrow paleae can be detected, and the interior cells are gorged 
with food, some of which is a highly refractive fatty substance staining bril- 
liantly with Sudan III. A small amount of starch also is present. In all prob- 
ability these tubers serve as organs of vegetative reproduction, but in view of 
their apparent rarity their efficiency in this respect is doubtful. Bolleter’* 
who has studied the tubers of the Conocephalum in some detail, emphasizes the 
fact that they are poorly adapted to withstand even short periods of dryness. 
In his experiments he rarely induced them to germinate at all and he suggests 
that our present Conocephalum may have descended from more xerophytic an- 
cestors, in which the tubers played a more important part than they do now. 
As the habit of the plant gradually grew more hydrophytic the tubers may 
have lost their xerophytic features, becoming in time vestigial in character. 
In Exrormotheca tuberifera Kashyap,’ a species recently described from the 
Himalayas, ventral tubers are associated with a distinctly xerophytic plant 
and apparently occur in abundance. No other instances of ventral tubers in the 
Marchantiaceae are known to the writer, although there are several cases in 
which the apex of an ordinary branch becomes tuberously thickened and often 
greatly modified. 
8. Asterella venosa (Lehm, & Lind.) Evans. 
Fimbriaria venosa Lehm. & Lind.; Lehm. Nov. Stirp. Pugill. 4: 29. 1882. 
Hypenantron venosum Trevis, Mem. Ist. Lombardo III. 4: 441, 1877. 
Thallus very delicate, sometimes thin throughout but not infrequently more 
or less tinged with purple, the pigmentation occasionally extensive but usually 
*Bot. Zeit, 45: 649-655. pl. 8. 1887. 
*Beih. Bot. Centralbl. 18: 897. 1905. 
“New Phytol. 13: 809, 1914. 
