Monographs Details: Hypolytrum jenmanii subsp. serratifolium (Uittien) T.Koyama
Authority: Maguire, Bassett. 1967. The botany of the Guayana Highland--Part VII. Mem. New York Bot. Gard. 17: 1-439.
Family:Cyperaceae
Description:Distribution and Ecology - Endemic to British Guiana. BRITISH GUIANA. Essequibo River, Moraballi Creek, near Bartica, near sea level, Sandwith 47 (K); Bartica, Jenman 2039 (Iv, XT); Potaro River, Waratuk portage, among stones in shade, Sandwith 1510 (K); Demerara River, Malali, Jenman 6660 (K); upper Mazamuni River, Kurupung, Leng 290 (NY) ; see also type collection.

Discussion:

Hypolytrum jenmanii C. B. Clarke var serratifolium Uittien, Rec. Trav. Bot. Neerl. 22: 344. 1924. Hypolytrum jenmanii C. B. Clarke, Kcw Bull. Add. Ser. 8: 49. 1908. In part, concerning Jenman 611S.

Type. British Guiana, Mazaruni River, Jenman 6118 (K, NY).

Subspecies serratifolium differs from subsp jenmanii in the leaf blades that are strongly serrate on the margins from the base to the apex and in its relatively larger habit. No mature fruits have been seen in any of the specimens. The two collections listed below appear to be intermediate between subsp jenmanii and subsp serratifolium by the relatively larger floral parts and longer leaf blades, which are, however, not serrate-scabrous on the margins except at the blade apex. VENEZUELA. Bolivar: Alto Rio Cuyuni, north portion of Cerro Uroi, alt 700 m, Rio Uroi, in forest on summit, Maguire, Stegermark & Maguire 53745. BRITISH GUIANA. Membaru-Kurupung Trail, Upper Mazaruni at alt 1000 m, occasional, Maguire & Fanshawe 32378. In 1925, H. Uittien (Rec. Trav. Bot. Neerl. 22: 344. 1924. ) pointed out that the syntype specimens of Hypolytrum jenmanii C. B. Clarke consist of two different entities. Having examined the related specimens I am in agreement with Uittien. One of the syntype specimens, Jenman 1944, from Waini Falls, Pomeroon District, has leaves that are serrate-scabrous only on the apical margins of the blades and smaller glumes 1.5-2 mm long. The second specimen cited by Clarke, Jenman 6118. from Mazaruni River, differs from the first plant by its leaves, which are serrulate-scabrous on the margins of the blades and of the less conspicuously petiolate base, and also in the larger glumes ranging from 3-3.75 mm long. This latter specimen has no mature fruits.

C. B. Clarke’s original description, which reads: “Folia , basi (i.e., lamina) in quasi-petiolum . subito angustata,” shows a better match with the first plant, i.e., Jenman 1944, than with the second plant. The fact that Clarke described a mature fruit in the original description suggests that the plant Clarke had in mind when he described it was the first plant. Uittien has, therefore, quite appropriately chosen it as the lectotype of H. jenmanii subsp jenmanii. Hypolytrum hoppioides Huber is another plant, which closely resembles H. jenmanii, yet it was not mentioned by Uittien in his treatment of the H. jenmanii complex. C. B. Clarke, who studied the type specimen of H. hoppioides, seems to have thought that it does not differ from Id. jennanii at least specifically since he annotated the type specimen as follows: "Hypol. hoppioides must be, I think, a starved state of this II. jenmani, with smaller heads, and without the additional glumes.” Nevertheless, Clarke eventually regarded H. hoppioides as specifically distinct (Clarke, 1908). Recently, I had the opportunity to examine the holotype of H. hoppioides in the Herbarium of Museu Goeldi at Belem, Brazil, and made certain that there is no difference between H. hoppioides and H. jenmanii subsp jenmanii. The two plants precisely match each other in both leaf and glume characters. The name, H. hoppioides Huber ex Clarke, is thus relegated to the synonymy. In the annotation Clarke implies that H. jenmanii has “additional glumes” in spikelets. I do not understand what the “additional glumes” indicate, as the spikelets of H. jenmanii consist of two squamellae exactly like those of a typical Hypolytrum species.

Distribution:Guyana South America|