246 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[vol. 10 



longiflora and P. galioides var. hispida, both types of flowers have been found. 

 However, in P. galioides var. densipila and var. intermedia only that type has 

 been found in which the anthers are included and the styles exserted. To a greater 

 extent as well, this latter condition is prevalent in the collections examined of 

 P. galioides var. hispida. 



The P. galioides complex is the most polymorphic of any of the specific taxa 

 treated within the genus, as shown 03- the large number of varieties and forms 

 recognized. Intergradations exist between the various infraspecific taxa and it 

 has been difficult to judge at which levels varietal and formal categories should 

 be drawn. As a whole, the many variations are held together by the 3-4-verticil- 

 late leaf arrangement, as opposed to the paired, decussate type found in the 

 P. hirsuta complex and in P. mexiae, and by the minutely scrobiculate seeds, 

 which contrast with the lineolate type characteristic of all the variations of the 

 P. hirsuta group. 



The tendency towards two main subspecific categories in P. galioides is man- 

 ifested by the var. densipila-inter media group on the one hand and by the var. 

 galioides-longiflora-hispida group on the other. The var. densipila-inter media 

 series is distributed chiefly in the eastern half of the range of P. galioides, center- 

 ing in the Gran Sabana in the state of Bolivar, Venezuela, whereas the var. 

 galioides-longiflcjra-hispida complex is encountered principally in the western half 

 of the geographical distribution, mainly in the upper Rio Orinoco and tributaries 

 in the Territorio Federal Amazonas of southwestern Venezuela. The calyx-divi- 

 sions of the var. densipila-inter m e dia group, which are strongly arched- to erect- 

 ascending with somewhat incurved tips, produce a more tightly compact head 

 than the more loosely spreading and often divaricately spreading to horizontal 

 (especially in the lower part of the head) calyx-divisions of the var. galioides- 

 longiflora-hispida series. However, since a number of collections are found which 

 are intermediate between the two main groups, it has seemed best to treat these 

 major variations as distinct varieties rather than as subspecies. In a number of 

 cases (Car dona 227a, Vareschi & Foldats 4730, Steyermark & Nilsson 620, Forest 

 Dept. 7835, and various others) it has been difficult to judge into which of the 

 various infraspecific categories certain intermediate collections should be placed, 

 as indicated in the discussions following the treatment of given varieties and 

 forms of P. galioides. 



4. Perama mexiae Standley ex Ste^-ermark. sp. nov. Fig. 81, A-E. 



Herba 1.5-4 cm alta annua, caulibus simplicibus erectis adpresso-strigosis 

 monocephalis ; f oliis oppositis rigidis adscendentibus 3-nervatis sessilibus lineari- 

 lanceolatis apice longe acuminatis vel subulatis 7-9 mm longis 0.8-1 mm latis 

 utrinque glabris, marginibus setoso-ciliatis setis 0.6-1 mm longis instructis, nervis 

 subtus prominentibus ; capitulis late oblongis 5-11 mm altis 6-7 mm latis; calyce 

 corollam fere aequanti, tubum corollae aequanti vel longiore quam eum, 4-4.5 mm 

 longo 0.3 mm lato rigide pectinato-ciliato cum 2 setis apicalibus 0.4-0.5 mm longis 

 instructo, ceteris setis lateralibus 0.8-1 mm longis ; corolla lutea 5.5 mm longa, 

 infundibuliformi-tubulosa, tubo superne parce graduatimque ampliato 4.25 mm 

 longo basi 0.5 mm lato apice 1 mm lato extus glabro intus infra apicem glabro 

 fauce pilosula, lobis ascendentibus triangulari- vel ovato-lanceolatis acuminatis 

 1.2 mm longis 0.5 mm latis extus parce breviter hirtellis intus glabris prope basin 

 papillatis ; staminibus 0.5 mm exsertis ; antheris oblongis subsessilibus in apicem 

 faucis insertis 0.8 mm longis, filamentis subobsoletis 0.1 mm longis; stylis 4.2-4.5 



