The English flora - SeaweedAfrica

M,G2E.
263
99. Desmidium. Frustula forming simple angular pseudo-
articulated filaments, hyaline at the eremite angles, at length se-
parating-.
)
Tribe XXIII. Fkagilaiuk.e. Filaments plane, extremelg
fragile, composed of rectilinear fr ust ula; ( frustula sometimes apparently
radiating from a centre and not presenting the appearance
of a Jilament.
100. FftAGILARIA. Frustula forming plane, p^eudo-artien-
lated, densely striated, fragile filaments, separating at the stria-
(not cohering at their angles).
101. Achnanthes. Frond stipitate, standard-shaped, coinposed
o£ fewfrustula, which at length separate (without cohering
at their angles).
102. Diatoma. Frustula forming pseudo-articulated, plane
filaments, at length separating and cohering at their angles.
103. Frlstllia. Frustula linear, free or imbedded in a
shapeless mass, solitary or binate.
TRIBE XXIV. Styllakik.i:. Frustula plane, wedge-shaped.
104. STYLLABIA. Frustula wedge-shaped, separate, stem-
less, not united into plane lamina'.
105. LlCMOPHORA. Frustula wedge-shaped, flabelliform,
stipitate.
106. Mebj'dion. Frustula wedge-shaped, in plane sessile
circles r segments of circles.
Tribe XXV. Cymbellrs. Frustula elliptical,
107. Gomphonema. Frustula subgeminate, terminating a
vt-iy Blender, Bimple or branchedfilament
108. HoM