Fig. 3. Porella piiinata L. 



A, Underside of stem, show- 

 ing ventral lobes andunder- 

 leaves. 



B, Leaf with ventral lobe. 



—34- 



I. Porella pinnata L. {Madotheca por. 

 ella Nees.) Fig. 3. Usually dark green 

 (sometimes yellowish-green), dull, somewhat 

 flaccid. Stems 2-3 pinnate, and loosely 

 matted together. Leaves distant or slightly 

 imbricate, curled or rolled in drying; ventral 

 lobes small, closely appressed, Ungulate ob- 

 long, margins plane or nearly so, length i-| 

 the width of the dorsal lobe. Underleaves 

 subquadrate, distant, scarcely decurrent, 

 nearly same width as stem, sometimes broader, 

 margins plane and entire. Perianth obovate- 

 pyriform, crenulate at mouth. 



At base and on exposed roots of trees sub- 

 ject to inundation, throughout eastern North America. Usually sterile. 



2. Porella Swartziana (Web.) Trevis. {Madotheca Swartziana 

 Lindenb.) Sordid green, dull; procumbent, irregularly pinnate, 3-5cm. long; 

 branches mostly short. Leaves subimbricate, dorsal lobes. ovate, entire or a 

 little wavy, lower margin decurved: ventral lobes linear-oblong, erect or 

 nearly so, margins plane, obtuse, nearly or quite entire, bearing 1-3 cilia at 

 base on inner margin, length \-\ the width of the dorsal. Underleaves 

 oblong, rarely exceeding stem in width, obtuse or truncate, margins plane, 

 entire above, ciliate-dentate at base, slightly decurrent. Collected in low 

 ravines at Opelousas, Louisiana, by Rev. A. B. Langlois (No. 228 and in 

 part No. 229). Type specimen is supposed to have been collected in Jamaica. 



3. Porella Wataugensis (Sulliv.) Underw. {Madotheca Wataugensis 

 SuUiv.) Similar to Porella pinnata, but differs in being smaller and more 

 delicate, and in the leaves, both dorsal and ventral lobes being subrepand- 

 denticulate. Collected by SuUivant on decayed logs on bank of the Watauga 

 River in North CaroHna. The only collection known. 



4. Porella rivularis (Nees.) Trevis. 

 Fig. 4. {Madotheca rivularis Nees. Porella 

 dentata Lindb.). Dull, dark green, flaccid; 

 irregularly pinnate, 3-iocm. long, prostrate or 

 ascending, forming rather loose mats ; dorsal 

 lobes of leaves subimbricate, obliquely ovate, 

 with rounded obtuse apex, entire or slightly 

 denticulate, flat or nearly so ; ventral lobes are 

 small, obliquely ovate, length \-\ width of the 

 dorsal, half as broad as are the underleaves, 

 the outer margin being mostly broadly revo- 

 rivularis, lute giving it a twisted appearance, long de- 

 current, usually dentate or ciliate at the inner 

 A Stem, showing under- ^^^^ underleaves distant, nearly or quite 

 leaves and leaves. 1 ^^ • -a^-x, r 



ventral orbicular, usually about twice the width of the 



Fig. 4. Porella 

 (Nees.) Trevis. 



B, Leaf, showing 

 lobe. 



stem, apex rounded, margins undulate, very 



