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Кіссіл | 81 
principal divisions obcuneate-oblong when young, becoming linear, 
3-5 times dichotomous, 6-15 mm. x 1-2.5 mm., lightly concave 
above, with thin, naked, slightly ascending. or plane margins ; the 
terminal segments commonly emarginate: monoicous: ostiolar 
papillae cylindrical, .06-.15 mm. high: capsules in a single or 
irregularly double series, rather prominent, the covering long in- 
tact; spores brown, darkening and rather opaque with age, 90- 
108 “in maximum diameter, distinctly angular, with a granulate- 
crenulate or minutely tuberculate margin 4—10 ит width, the prom- 
inent ridges of the outer face rather irregularly anastomosing, the 
areolae of the middle of the face, when well defined, usually very 
large (20-45 pin diameter) and often enclosing an isolated tubercle 
or a free-ending spur, the inner faces mostly with tubercles and 
short free irregular ridges, sometimes with imperfect areolae. 
On wet soil in the bottom of a deep сайоп, Santa Catalina 
Island, A. J. McClatchie, Sept. 15, 1893, no. 441. | 
Riccia Catalinae is а near ally of К. crystallina L. from which 
it differs in the larger size, in the finally 3-5 times dichotomous 
more elongated divisions, which are less closely adnate to the soil, 
іп the larger spores (60-90 м in the various European specimens 
of R. crystallina examined), in the much less regular areolation of 
the spore-faces, and in the considerably larger size of the central 
meshes of the outer face, when these are well-formed. 
The thallus is so thin and so largely occupied by air-chambers 
that we have been unable, from the dried material, to obtain any 
satisfactory sections. 
PLATE 91, Fics. 16-20. Ricca CATALINAE. 
16. Portion of thallus, dry, natural size. 
17. End of young terminal lobe, dorsal surface, showing position of the internal 
lamellae which bound the air-chambers, >< 23. rom a soaked-out fragment. 
18. Dorsal view of thallus in the older parts, Х 23. 
19. Spores, Х 305. 
IO. Riccia CRYSTALLINA L. Sp. Pl. 1138. 1753. 
Thallus in closely attached orbicular or suborbicular rosettes 
5—15 mm. in diameter, light green on both sides or often tinged with 
yellow, spongiose with age and vesiculose-alveolate; the principal di- 
visions mostly lobate-obcordate or obcuneate, or sometimes becom- 
ing broadly linear and 1-3 times furcate, the segments often close 
and somewhat crowded, terminal lobes 1.5-2.5 mm. wide, transverse 
sections 2.5—4 times broader than high, margins naked, subobtuse, 
slightly elevated on drying or nearly plane, ventral scales wanting ; 
