CONVOLVULACE^E 285 



the invaginated tegmen extending some way down the interior of the 

 dorsal aspect of the seed where it becomes shallow and extends to 

 the hilum. Hence the notch in the cotyledons is caused by their 

 growing at the sides after their apex has reached this ridge. 



Seedling-. 



Primary root elongated, tapering, with numerous lateral branch- 

 ing fibres. 



Hypocotyl erect, terete, glabrous, green or purplish, stout, 7- 

 15 mm. long. 



Cotyledons large, foliaceous, broadly oblong, truncate and shal- 

 lowly emarginate above, truncate or abruptly cuneate at the base 

 where they are five-nerved, alternately nerved upwards ; nerves 

 strong, forking, the midrib generally though not always proceeding 

 to the tip, sometimes forking a little way below it, light green, 

 glabrous ; lamina 2-2'8 cm. long, l'9-2'65 cm. wide ; petiole semi- 

 terete, channelled above, 2 to 2'5 cm. long. 



Stem herbaceous, at first erect, afterwards twining from right to 

 left or against the sun, above the first or second true leaf, terete, 

 glabrous, twisted after commencing to twine ; internodes very vari- 

 able, 1st 3'4-6'5 cm. long ; 2nd almost undeveloped to 3 cm. ; the 

 rest longer. 



The first two branches originating in the axils of the cotyledons 

 are geotropic, deep red, and resolve themselves into underground 

 rhizomes or creeping stems, with small scale-like leaves. If the 

 main axis should by any accident be broken off, the branches from 

 the cotyledons assume the appearance and characters of the primary 

 stem, and perform the same functions. 



Leaves simple, cauline, alternate, exstipulate, petiolate, glabrous, 

 light green, five-nerved at the base, alternately nerved upwards with 

 somewhat incurved, anastomosing nerves ; petioles semiterete, gla- 

 brous, channelled above, frequently twisted at the base to bring the 

 blade of the leaf to the light. 



No. 1. Cordate-subhastate, cuspidately acute, with the lower pair 

 of lateral nerves running into the obtuse angles. 



No. 2. Cordate, elongated, cuspidately acute or having an odd, 

 obtuse angle on one side. 



Nos. 3 and 4. Cordate, elongated, cuspidately acute. 



These characters are liable to variation, and sometimes all the 

 early leaves are simply elongated-cordate. In one specimen noted 

 the first two leaves were exactly like the cotyledons, but smaller and 

 rather more deeply emarginate. 



Ultimate leaves hastate or sagittate, always with a deep basal 



