2957] 



THE BOTANY OF THE GUAYANA HIGHLAND— PART II 



331 



parts of Venezuela and Colombia. The two species so far known — H. brasiliense 

 and H. spruceanum — are very closely related, and it might possibly be more 

 correct to unite them into one species. The genus is characterized by the greatly 

 reduced size of its outer petals; these are strikingly smaller than those of the 

 inner whorl, and in the species so far known very like the sepals. In H. brasi- 

 liense the sepals and outer petals are of equal size and short-pointed, but in 

 H. spruceanum they are protracted into narrow tips. In our variety longipetala, 

 which in respect of its vegetative parts is closely related to H. spruceanum, 

 the outer petals — in the rest of the genus short and sepal-like — are nearly 2 cm 

 long; the fact that they are directed outwards and arched backwards in a peculiar 

 way is very striking. 



The great reduction of the outer petals into sepal-like shapes which charac- 

 terizes the genus Heteropetalum, has previously led some authors to attach the 

 genus to the Miliusa group of the Annonaceae. In a paper published in 1942 (in 

 Arkiv for Botanik) the present writer has, however, tried to show that this charac- 

 ter is not particularly important from a systematic point of view, and that in other 

 respects this genus fits well into the Guatteria section of the Annonaceae system. 

 The fact that a type like the variety described here has been found to have long 

 outer petals quite different from the sepals provides additional support for the 

 opinion that the relationship of Heteropetalum to the Miliusa group is not very 

 close. 



DROSERACEAE 



Drosera L. 



Specimens of Drosera recently collected in Guayana include with few ex- 

 ceptions all species now known for Venezuela. The following key leads to the 

 material at hand from Guayana and Venezuela. 



Key to the Species of Drosera 



1. Styles 3 or 5, not bipartite. 



2. Styles 3, ramiform-penicillate at the tips; stems branched-fastigiate; leaves 

 with obvious petioles; scapes lacking; flowers solitary and short-pedicellate; 

 seed 0.6-0.8 mm long, oblong, finely foveolate in 16-18 vertical lines; 

 sect. Meristocaulis. 1. Drosera meristocaulis 



2. Styles 5, ramiform-penicillate at the tips; leaves without obvious petioles; 



scapes 10-20 cm iong, glabrous or sparingly glandular-pubescent; seed 

 elliptic-ovoid, ca. 0.3 mm long, biapiculate, foveolate in 8-10 vertical 

 lines; sect. Thelocalyx 2. Drosera sessilifolia 



1. Styles 3, bipartite to the base; sect. Drosera. 



3. Scapes evidently or strongly pubescent or glandular-pubescent. 

 4. Scapes stipitate-glandular. 



5. Leaves 2 cm or less long. 



6. Scapes 10-25 cm long, moderately or strongly stipitate-glandular, (5) 

 10— 15~flowered; leaves strongly fuscous-strigose-pilose beneath; 

 seed subclavate, 0.8-1.0 mm long, prominently bullate-papillate. 



3. Drosera roraimae 



6. Scapes 5-8 cm long. 



7. Scapes sparingly stipitate-glandular-pilose, mostly solitary, some- 

 times 2-3, 2-4-flowered; leaves glabrous beneath; sepals oblong- 

 ovate, erose-denticulate, externally pilose; seed "obovoid, foveo- 

 late." 4. Drosera cayennensis 

 7. Scapes and inflorescence conspicuously pilose-stipitate-glandular, 

 mostly 2-5, sometimes solitary, 2-4-flowered; sepals acutish; 

 seed 0.3-0.4 mm long, subglobose, foveolate in vertical lines. 



5. Drosera arenicola 



