15G 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[vol. 10 



Tryssophyton merumense Wurdack, sp. nov. Pig. 67, g-k. 



Herba simplicicaulis plus minusve glandulis rubris sessilibus praedita ; caulis 

 usque ad folia gracilis 5-12 cm. Folia ad caulis apicem vel rare etiam ad caulis 

 medium 10-14-verticillata sessilia vel petiolis alatis 2-4.5 X 0.3-0.5 cm oblance- 

 olata vel elliptico-lanceolata apice late acuta vel obtusa basi anguste acuta tenuiter 

 membranacea, supra sparsissime strigulosa, subtus glabra, ad margines conspicue 

 subremoteque ciliolato-serrulata inconspicue trinervata. Flores solitarii vel 

 geminati glabri ; pedunculus nullus (in floribus solitariis) vel 1.5-2 cm longus; 

 pedicelli 8-15 mm longi glabri apicem versus 4-alati ad basim bracteolati, 

 bracteolis 0.5-1 mm longis subulatis mucronulatis. Hypanthium (ad torum) 

 2.1 X 2 mm leviter 8-costatum ; calycis tubus 0.1 mm altus, lobis 1.1-1.3 mm 

 longis subulato-triangularibus anguste acutis. Petala 11 X 6 mm asymmetrice 

 elliptica apice abrupte acuta apiculataque. Filamenta 4.5 vel 3.3 mm longa ; 

 antherarum thecae 2.3 vel 1.6-1.7 X 0.5 mm apice vix (0.1 mm) rostratae et 

 minute (0.1 mm diam) uniporosae, connectivo basi thecis coalito et ad 0.55- 

 0.65 X 0.4 mm incrassato ventraliter 0.1 mm bilobulato dorsaliter truncato. 

 Stylus 10 X 0.2 mm ; stigma truncatum ; ovarium ad anthesim ca. 1 mm altum 

 apice in collum 0.4 mm altum et ad 0.2 mm 4-lobulatum (lobis truncatis) 

 protractum. Fructus maturus ignotus. 



Type. Petals 1/2 white with exposed bud surfaces deep pink, anthers yellow, 

 fruiting pedicel translucent green suffused with pink, common on mossy logs 

 in forest, Merume Mountain, Partang River, upper Mazaruni River basin, 

 Pakaraima Mts. } British Guiana, elev. 1140 m, 4 Jul 1960, Stephen S. Tillett, 

 Carolyn L. Tillett, & Rufns Boy an 43988 (holotype US 2343844). 



In vegetative habit, Tryssophyton is very distinct from all known Bertolonieae 

 and Sonerileae. In Cogniaux' keys, the closest New World relative would be 

 Bertolonia, the closest Old World one Bar copy ramus. In Brenan's synopsis of 

 the African Sonerileae (Kew Bull. 85-89. 1953), apart from the habit, Trysso- 

 phyton seems to key to Gravcsia or Cincinnobotrys ; both genera have somewhat 

 different stamens. Neither Bakhuizen van den Brink's treatment of Malaysian 

 Melastomataceae (Rec. Trav. Bot. Neerl. 40. 1943-45) nor Li's revision of the 

 Chinese genera (Jour. Arnold Arb. 25. 1944) offer an}* relationship clues. The 

 longitudinally bicolored petals of Tryssophyton are like those of Macrocentrum 

 pusillum Gl. and M. glandulosum Gl. I do not believe that great importance 

 should be attached to the 4-celled ovary of Tryssophyton, since both paucity of 

 material and difficulty of dissection have prevented accurate knowledge of the 

 constancy of 3-celled ovaries in the New World Bertolonieae ; my own dissection 

 notes on M. pusillum and M. gracile Wurdack, as well as Dr. Gleason's dissection 

 notes on M. fruticosum GL, indicate the occurrence of 2- or 4-celled ovaries. In 

 any event, both the whorled leaves and Marcetia-like stamens set Tryssophyton 

 apart from other Bertolonieae. 



Macrocentrum brevipedicellatum Wurdack, sp. nov. 



M. vestito Sandw. affinis sed floris fructusque pedicellis brevioribus. 



llerba pusilla ad 12 cm alta; ramuli petiolis foliisque -modiee breviterque 

 setosi pilis gracilibus simplicibus ca. 1-1.3 mm longis. Folia membranacea in 

 quoque jugo disparilia uninervata ciliata integra vel indistincte crenulato- 

 serrulata; folia maiora 4-7 mm petiolata, lamina 1-2.7 X 0.6-1.4 cm elliptica 

 vel vix obovato-elliptica apice obtusa vel rotundata basi late acuta ; folia minora 

 1-2 mm petiolata, lamina 2-5 X 2-4 mm orbiculari vel late ovata. Flores 4-meri 



