64 PROCEEDINGS OF THE AMERICAN ACADEMY. 
In 1881 Hemsley ! credited to Mexico 24 species of Pectis, though some 
of them doubtless cannot stand. P. Liebmannii, Sch. Bip., one of the 
best marked species of § Pectothrix, was described as new; and since the 
publication of Hemsley nine additional Mexican species have been de- 
scribed. 
In 1883? Dr. Gray discussed the genus Pectis, making many critical 
notes upon the species. He at that time modified his division of the 
genus, so that he recognized only three sections : — 
1. Euprctis. Pappus paucipaleaceus, vel pauci-aristatus aristis setiformi- 
bus, nunc ex aristis et paleolis paucis vel definitis constans, plerumque uniseriali 
ECTOTHRIX. Pappus (saltem fl. disci) multisetosus, inaequalis, ple 
rumque biserialis, setis int ioril lidiorib d istifi ibus inf 
sensim latioribus nec vero paleaceis. 
3. Pecrrprum. Pappus bi-tricornis, nempe ex aristis paucissimis 
validis corneis seepius divergentibus. 
a 
(4) 
This division was followed in the Synoptical Flora, where P. Rusby, : 
Greene, from Arizona, was described as new. 2 
Two species, P. gibbosa and P. linearis, have been published in @ recent 2 
number of La Naturaleza‘ from old descriptions written by La Llave 
1832. These descriptions, however, contain so little of a specific nature é 
that it is impossible to tell from them alone what the plants may be. me 
The genus Peetis is, as Dr. Gray has remarked, a very natural one} " 
fact, it presents such intergradations that it is difficult to get a really sats 
factory basis for division into sections. Habital characters in such & group, 3 
with many short-lived annuals, are very unsatisfactory 
plants ordinarily perennial with a suffruticose base may deve 
The color of the rays, the number and length of the basa 
leaves, and the distribution of glands, are all characters so inconstant 
to be of only minor importance. The only character which asgaen si 
ciently constant, at least for the larger divisions into subgenera, 1s 10 4 
pappus, and even that presents some obstructions to the making of cleat a 
‘ 
Ss 4 
defined groups. ae 
In yaskouns to group all the United States and Mexican species, it 
seems that the best results are attained by a compromise eee ) 
Gray’s recent treatment of the genus (Proc. Amer. Acad. xix. 4 pee 
and his earlier division of it in Plante Wrightiane (i. 83). The sastil 
genus Heteropectis is sufficiently unique, apparently, in its retrorsely bare” 
1 Biol. Centr.-Am. Bot. ii. 224-227. 8 Gray, Syn. FI. i. pt. 1, 360- 
2 Proc. Am. Acad. xix. 43-48. 4 La Nat. vii. Append. 84 
