Mygdykitia

Name

Mygdykitia

Rank

Genus

Authors (Pub.)

Golovneva L. B. Shczepetov S. V.  

Publication

Yanskij floristicheskij kompleks iz verkhnemelovykh vulkanogennykh otlozhenij Severnogo Priokhot'ya [2013]

Journal

Paleobotanika

Volume

4

Page number

9

Year

2013

Parent Taxon

[Family] Dipteridaceae

Fossil Status

foliage

Type

Mygdykitia ochotica

Diagnosis

Fronds pinnate, linear-lanceolate, tapering in apical direction, 8—15 cm long and 1—2,4 cm wide, with thin rachis about 1—1,5 mm in diameter. Pinnules borne laterally in one plane, subopposite, more than 17 pairs in number, 8—12 mm long, 4—6 mm wide, gradually reduced in sizes towards frond apex. Basal part of the rachis (about ¹⁄₅ of length) has no pinnules. In the middle part of the frond the pinnules arising from the rachis at angle of about 90°, oblong or ovate-lanceolate in shape, with contracted truncate-rounded sessile base and triangular, sometimes attenuate apex, which ended by blunt tooth. Margin is entire, waved or crenate. Most part of pinnules has three teeth near apex, some basal pinnules have up to 2—4 teeth from each side. Teeth triangular with rounded apex, forward directed, 1—1,5 mm in length. Towards frond apex the pinnules arise from the rachis at angle of 70—90°, becoming triangular, slightly curved, with rounded apex and wide sessile base, margin usually entire. Basal pinnules arise from the rachis at angle of 90—110°, ovate or ovate-lanceolate, with narrowed asymmetric base contracted on acroscopic side and slightly contracted or decurrent on basiscopic side, sometimes base rounded with short petiole. In the upper part of frond the pinnules are closely disposed, sometimes with fused bases. Towards the frond base the distances between pinnules gradually increase up to interval in 2—5 mm. The midrib of pinnules is straight and distinct, other veins are thin, poorly ranked. The midrib bearing 2—4 secondary curved branches from each side, arising from the midrib at angle of about 60—70° and ending in teeth or forming loops. Venation of higher orders is reticulate. Final meshes are polygonal or quadrangular, with rounded angles, 0,3—0,4 mm in diameter, with free-ending veinlets inside.