92 University of California Publications in Botany [Vol. 6 



dermis; cystocarps narrow or broadly pyriform (according to age), 

 135-195/x (T & R), broad and rounded at the base and tapering gradu- 

 ally from just below the middle to the carpostome ; gonimoblasts 

 slender, numerous, crowded, radiating upwards and inwards from a 

 placental group of a few large cells, forming a dense pyriform mass, 

 abjointing oblong spores in succession ; pedicel distinct ; periderm of 

 2-3 layers, coarsely pseudoparenchymatous below, separating into 

 distinct filaments above. 



The structure of Scinaia furcellata is of importance, since this 

 species is the type of the genus and all considerations as to generic 

 agreement or disagreement must be settled, or at least discussed, on 

 a basis of comparison with Sc. furcellata. The axis of the frond in 

 the various specimens examined is comparatively broad and made up 

 of a few larger filaments, parallel to one another or very loosely 

 entwined, surrounded by few to many very slender, more or less 

 intricately entwined corticating filaments. The horizontal, later 

 "ascending" filaments are numerous above but more scanty below. 

 The cortex is made up of three layers, the epidermal layer, the hypo- 

 dermal layer, and a layer of corticating filaments. The corticating 

 layer is fairly broad and made up of slender filaments, arising from 

 the cells of the ascending filaments as well as from those of the 

 hypodermal layer. These slender filaments are vertical, oblique, or 

 nearly horizontal in their course and loosely entwined. The hypo- 

 dermal layer is made up of two to three layers of colored cells of 

 various shapes according to situation in the plant (i.e., according to 

 age and development). When yoimger (i.e., above) they are spherical 

 to ovoid, becoming elongated and obovate or clavate with age (i.e, 

 below). The epidermal layer is composed of cells which are colored 

 or very nearly alike at first, but soon begin to differentiate. Certain 

 of these cells, regularly placed, enlarge and become lighter colored, 

 until, at maturity, they are swollen and seemingly devoid of solid 

 contents. Their shape varies according to age and development. 

 At first globular (cf. fig. 2, pi. 10), or very nearly so (cf. fig. 3. 

 pi. 10), they later become larger and flattened (cf. fig. 5, pi. 10) or 

 oblong (cf. fig. 5, pi. 10), then elongated and narrowed more or less 

 above (cf. fig. 4, pi. 10), but at maturity they agree in being obovate 

 or inversely pear-shaped (cf. figs. 6-11, pi. 10), the outer end being 

 obtusely rounded and the inner end contracted. These large hyaline 

 cells of the epidermal layer are the so-called utricles. Among them 

 are scattered elongated, slender, colored cells, which later bear the 

 antheridia. In Scinaia furcellata, so far as the material examined 



