1958] 



THE BOTANY OF THE GUAYANA HIGHLAND— PART III 



81 



may be opposite the middle of a calyx-lobe, the next near one margin or another 

 of an adjoining lobe, and a third in the interval between two calyx-lobes. This 

 lack of symmetry suggests the possibility that the structures which are appar- 

 ently calyx-lobes are not in actuality members of a true floral whorl, but have 

 resulted merely from the random splitting of the hypanthium. If this be true 

 it represents additional confirmation for the assignment of this species to Mar- 

 lierea rather than to Myrcia. Evidence as a whole seems to point to such a dis- 

 position of the four taxa assigned to this section. 



Specific lines are not clearly drawn in this section. Mr. N. Y. Sandwith ob- 

 served some years ago that M. guildingia/na is scarcely to be separated from M. 

 bipennis except by the strongly winged branchlets in the latter, and the weak 

 development of wings in the former. Additional materials from intermediate sta- 

 tions in northern Brazil and southern Venezuela may serve to clarify the status 

 of the several taxa. At present they may be regarded as distinct and distinguish- 

 able species. They are geographically isolated from one another as far as known, 

 and although the morphological differences between them are trivial they are 

 constant as far as one can tell. 



18. Marlierea biptera Amshoff, Rec. Trav. Bot. Neerl. 42: 3. 1950. 



For description see Amshoff. I.e., or Fl. Surin. 3: 68 (1951). Known only 

 from the type, collected in eastern Surinam. The branchlets are winged as in 

 sect. Myrciopsis, but the relatively abundant pubescence, the coarse and many- 

 flowered panicles, the large buds (probably 5 mm long) and the dehiscent calyx 

 indicate that M. biptera is not closely related to the species of this section. 



19. Marlierea buxifolia Amshoff, Bull. Torrey Club 75: 529. 1948. 



For description see Amshoff, I.e. Known only from British Guiana, the type 

 from the Kajetur Savanna. 



20. Marlierea caesariata McVaugh, sp. now 



Arbor 12 m alta, velutina, paniculis ramulisque novellis, pilis runs appressis 

 lucidis simplicibns, 0.5 mm longis obtectis ; ramulis exalatis; foliis 10-21 cm 

 longis, aeuminatis; nervo medio supra planiusculo vel convexo; venis non im- 

 pressis; petiolis 10-20 mm longis; paniculis eirciter 20-floris, in alabastro 4—6 cm 

 longis; bracteis ut videtur deciduis; alabastris 4-4.5 mm longis non omnino 

 clausis. 



Tree to 12 m high, the inflorescence and young growth velutinous, very thick- 

 ly covered with coarse, lustrous, antrorsely curved and appressed, unbranched 

 pointed reddish-brown hairs 0.5 mm long (caesariata, having a beautiful head of 

 hair) ; leaves elliptic, (3.5-) 6-10 cm wide, (10-) 15-21 cm long, 2-3 times as 

 long as wide, about equally narrowed to the abruptly acuminate tip and the 

 acute base where somewhat trough-shaped; margins long-decurrent on the petiole 

 1.5-2 mm thick, 10-20 mm long; midvein flat or convex above, the whole some- 

 times impressed, prominent beneath; lateral veins 15-20 or more pairs, including 

 some intermediates, slightly elevated on both sides, more prominent beneath ; 

 marginal vein about equaling the laterals, somewhat arched between them, 1-2 

 mm from margin ; blades lustrous above, paler beneath, obscurely dotted on both 

 surfaces; inflorescence axillary and terminal, the panicles in bud 4-6 cm long, 

 twice compound, about 20-flowered, the flowers clustered near the tips ; peduncle 

 2-3.5 cm long, compressed, 2-3 mm wide near summit ; bracts 4 mm long, lanceo- 

 late, attenuate; bracteoles similar, lance-linear, 3 mm long; buds 4-^.5 mm long, 



