1. Lemna.] 133. LEMNACE.^. 



1. Root 1: — 



a. Frond entire, branches obovoid, soon detached : — 



Frond asymmetric nearly tiat both surfaces . . . I. paucicostata. 



Frond orbicular or/obovoid opaque, tumid beneath . . 2. ijibba. 

 h. Frond with serrate tip. Branches hastate persistent . 3. trisulca. 



2. Roots more than one (Spii-odela, vide s^ujn-n) : — 



Frond herbaceous, broadly obovate to orbicular 7-nerved 4.- poli/rrhisa 

 Frond membranous shining ovate or oblong 3-o-nerved . 5. oligorrhiza. 



Herbaria contain very few specimens of Lemna from our area, nor have I found 

 t i me to collect them. In view of the widespread nature of these aquatics, however, 

 it is probable that all the following, the descriptions of which I have to a great 

 extent borrowed from Sir J. D. Hooker, will be found. 



1. L. paucicostata, Hegelm. 



Frond asymmetric, obovate or obovate-oblong, nearly flat on both 

 siirfaces, entire. Root 1, with acute root-cap. Ovule solitary. 



Apparently throughout India, extending from Moradabad to Ceylon and IChasia. 

 Santal Pargannahs, in stagnant waters, common. Kurz. ! Probablj* in all 

 districts. 



2. L. gibba, L. 



Frond symmetric, orbicular or obovoid, tumid beneath, entire, 

 opaque, epidermis with flexuous walls, cells beneath very large. 

 Eoot 1, root-sheath elongate, cylindric, root-cap acute. Stamens 2. 

 Ovules 2-7. Utricle circumsciss. Seeds erect, anatropous. 

 Still waters throughout India, J.D.lf. 



3. L. trisulca, L. Ivy-leaved Duckweed. 



A ver}^ distinct species from the lanceolate or oblanceolate daughter 

 fronds being hastately attached and their remaining attached towards 

 the middle or base of the parent shoot and in their turn often bearing 

 1-2 lateral younger fronds ; the shoots or daughter-fronds ultimately 

 develop a slender very tapering base, are often somewhat hastate and 

 are more or less serrate at the tip ; nerves 1 towards the base and three 

 towards the apex. Root 1, Avith acute cap. Ovule solitary. 



Bengal, lioxb. and Kurz ! Not specifically I'ecorded from our area bat I think I 

 have seen it and it is likely to occur. 



4. L. polyrrhiza, L. Syn. Spirodela polyrrhiza, Schleid. 



Fronds large orbicular or orbicular-obovate and up to -3" long, 

 herbaceous flat or nearly so, 7-nerved towards apex and I towards 

 base, usually purplish beneath. Roots several. Spathe 2-lipped. 

 Stamens 2. Ovules 1-2. 



A common species, probably throughout the province. Bengal, Griffifh, Kurz, 

 and others without definite locality ! 



5. L. oligorrhiza, Kurz. 8yn. Spirodela oligorrhiza, Heglm. 



Fronds elliptic-oblong, membranous, •15--2" long, 3-5-nerved, 

 purple beneath, collected in circinate groups. Roots 2-5 very long. 

 Spathe 2-li2)ped, stamens 2. Style long. Ovule 1. 



Bengal, frequen% K 



874 



