A REVISION OF THE GENUS HAMELIA 215 



Venezuela : Moritz, 464 ! Fendler, 591 ! Ecuador : Spruce, 6226 ! 

 Sinclair \ Peru: Ule, 6469! Spruce, 4188! Matthetvs, 1498! 

 3135! Brazil: Bieclel, 199! 423; Blanchet, 4, 101, 1359! Weir, 

 77 ! St. Hilaire ! Glocker, 148 ! Burchell, 7405 ! i?er/?jeZZ, 132* ! 

 Neuivied, 84; Claussen, 272 a; Mendonca, 160; Schenck, 3741; 

 Glaziou, 706 ; Mose?i, 1348, 4170 ; Pohl, 5134 ; Sello, 626, 1229, 

 1791. Bolivia: Banj/, 1222 ! BnVZ(/es, s. n. ! Paraguay: Hassler, 

 5212! 6854! 7773! 10,283! Fiebrig, 4260! Hb. Mus. Brit.; 

 Hb. Kew ; Hb. Univ. Cambridge. 



This species, which has of all the widest distribution, is also 

 so variable that the task of finding constant and critical characters 

 is one of considerable difficulty. Some stress has hitherto been 

 placed upon the number of leaves at each node ; and in so far as 

 the distinction lies between the opposite and the whorled arrange- 

 ment, this seems to be constant for the species respectively con- 

 cerned. The numbers three or four, however, are rarely constant 

 for any species. In H. pateyis the number three is certainly by 

 far the commonest, and this number appears in previous descrip- 

 tions ; but the 4-nate arrangement is to be found, e. g. in the 

 herb. Miller specimen (Hb. Mus. Brit.); in /. D. Sfiiith, 1974; in 

 Fl. Trinitatis, 32 ; in Barclay, s. n. (Hb. Kew.) ; in Spruce, 6226 ; 

 in Zimmermann's plant from Siam cited above ; and in a specimen 

 cultivated by Henslow in the Cambridge Botanic Garden, and 

 preserved in the University Herbarium. 



The 5-verticillate arrangement occurs in the following plants 

 gathered in two widely separated districts : — Costa Eica, Tonduz, 

 12,813; Cooper, herb. J. D. Smith, 5790: Honduras, Barclay, 

 2664 : Bolivia, Bang, 1222. In all the circumstances it seems 

 doubtful whether De Candolle's variety y qidnifolia (Prodr. iv. 

 442), founded upon a plant collected in Mexico by Mo^ino & Sesse, 

 should be maintained. I have not seen this plant ; but those 

 cited above differ from the normal H. piatens in no way save the 

 number of leaves in a whorl, and this cannot be regarded as a 

 constant feature. 



The indumentum of the leaf, moreover, is very variable in 

 extent. In some cases both sides of the leaf have a hairy covering, 

 that of the upper being, however, much less conspicuous than that 

 of the lower side ; the ventral surface, indeed, is often glabrescent 

 and even quite glabrous. The dorsal indumentum shows every 

 transition from an almost woolly character to minute pubescence 

 confined largely to the veins. In the former case H. j^atens is 

 nearly linked, apparently, with H. lanuginosa, a species which 

 I have had no opportunity to examine. In the forms which 

 approach glabrescence, H. ixitens reveals affinity with the glabrate 

 group (species 14-22), typified in H. papillosa, H. pedicellata, 

 H. versicolor, and H. viridifolia. The more sparsely pubescent 

 forms of H. patens may be distinguished primarily from the 

 members of this latter group by the presence of pubescence on 

 the veins of the third order, as well as on the median and secon- 

 dary veins, and, as a general rule, between the veins as well as 

 upon them. 



