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PALAEOBOTANY OF THE MESOPHYTIC II
Author(s) -
CITTERT JOHANNA H. A.
Publication year - 1966
Publication title -
acta botanica neerlandica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0044-5983
DOI - 10.1111/j.1438-8677.1966.tb00233.x
Subject(s) - herbarium , paleobotany , mesophyte , lichen , geography , botany , biology , biochemistry , plant development , deciduous , gene
Diagnosis: Frond at least bipinnate. Rachis up to 2 mm broad, longitudinally grooved. Pinnae alternate or subopposite, up to 1,5 cm broad (normally 1 cm), longest one 5 cm long but without apex. Pinnae arising at intervals of 1-2,5 cm, and at an angle of 30-60°. Pinna-rachis thin. Pinnules arising at an angle of 45° at intervals of 1-6 mm, alternate, katadromic. Pinnules always united basally. Pinnules in the lower (or middle) part of the leaf linear, up to 1,5 cm long (normally 1 cm) and up to 4 mm broad (normally 2 mm). Apex obtuse, margin entire, slightly narrowed near the base, basal margin decurrent as a narrow wing along the pinna-rachis. In the upper part of the leaf pinnules smaller, 4 mm broad, 6 mm long, deltoid and slightly falcate. Proximally the pinnae are pinnulate, the pinnules becoming first laterally fused and then forming an entire pinna. Venation: Midrib arising at a small angle near the basal edge of the pinnule and bending outwards or, sometimes, straight to the apex. Lateral veins arising in katadromic order or nearly opposite, at intervals of 1-2 mm and at an angle of 40°, simple or once forked half-way towards the margin; branches diverging.