Heliotropium perrieri J.S. Mill., 2003

Miller, James S., 2003, A new species of Heliotropium L. (Boraginaceae) from Madagascar, Adansonia (3) 25 (1), pp. 115-118 : 116-117

Heliotropium perrieri J.S. Mill. , sp. nov.

Herba annua usque ad 15 cm alta, caulibus erectis. Folia alterna, sessilia vel petiolo usque ad 3 mm longo insidentia; lamina lanceolata usque anguste elliptica , 10- 20 mm longa, 2-5 mm lata, apice acuta, basi attenuata usque cuneata, margine integra, adaxialiter glabra vel sparse strigosa, abaxialiter strigosa. Inflorescentia e flobibus solitariis ex axillis bractearum foliacearum ortis constans. Flos sepalis lanceolatis, 1.7-2 mm longis; antheris sessilibus, ad apiceum connatis. Fructus ovoideus, c. 1 mm longus, maturitate in 4 nuculas reticulatas ad secedens.

TYPUS. — Perrier de la Bâthie 4420, Madagascar, Prov. Mahajanga, bords un peu sales de la plaine de Marovoay, sur les sables très humides, fl., fr., Jan. 1910 (holo-, P!; iso-, MO!, P!) .

Annual herb, the stems erect, to 15 cm tall, with sparse, appressed hairs,> 0.5 mm long. Leaves alternate; blades lanceolate to narrowly elliptic, 10-20 mm long, 2-5 mm wide, the apex acute, the base attenuate to cuneate, the margin entire, slightly thickened or minutely revolute, the adaxial surface glabrous to sparsely strigose, evenly strigose on the midrib, the abaxial surface evenly strigose, the hairs from a basal cystolith, the midrib impressed on the adaxial surface, raised on the abaxial surface, the secondary and tertiary venation obscure; petioles short and the leaves sessile or rarely to 3 mm long, sparsely strigose. Flowers bisexual, borne individually in the axils of leafy bracts, on short pedicels 1-2 mm long, these strigillose; sepals lanceolate, 1.7-2 mm long, 0.5 mm wide, the apex attenuate, strigillose; corolla white with a yellow throat, 3-3.5 mm long, the 5 lobes spreading, elliptic to ovate, 1.3- 2 mm long; anthers sessile, inserted near the base of the corolla, c. 0.5 mm long, connate at the apex; ovary globose, c. 0.3 long, 0.3 mm wide, the stigma nearly sessile, c. 0.3 mm long. Fruits depressed ovoid, c. 1 mm long, c. 2 mm wide, 4 lobed and separating into 4 nutlets at maturity, these tan, glabrous, reticulate on the dorsal surface, the sessile stigma persistent. — Fig. 1 .

Heliotropium perrieri is distinctive among the Malagasy species in its annual habit, its solitary flowers, and in having four rounded nutlets with a reticulate outer surface. In Madagascar, H. perrieri is most easily confused with H. baclei DC. , which differs in being perennial, evidently pubescent, and having the flowers evenly distributed along the stems in the axils of leaves as opposed to having flowers borne at the apex of stems in the axils of leafy bracts.

DISTRIBUTION. — Heliotropium perrieri is known only from Mahajanga province near Antanimena where it occurs on wet, salty soil. — Fig. 2.

CONSERVATION STATUS. — Provisional IUCN Red List Category: Endangered (EN B1abi-iv + B2abi-iv). With a very limited Extent of Occurrence and Area of Occupancy, in a highly disturbed area, this species must be considered at significant threat. It is not known whether it survives in disturbed areas or whether it grows only at the margin of undisturbed wetlands. The species has not been collected since 1929.

PARATYPES. — MADAGASCAR: Perrier de la Bâthie 1369, Prov. Mahajanga, plateau d’Antanimena, entre le Betsiboka et le Mahavavy, 16 o 29’S, 46 o 11’E, fl., fr .,

Oct. 1901 ( P!) ; Perrier de la Bâthie 12343, Prov. Mahajanga, Antanimena , 16 o 29’S, 46 o 11’E, fl., fr ., Feb. 1919 ( P!) ; Perrier de la Bâthie 16826, Prov. Mahajanga, Antanimena , 16 o 29’S, 46 o 11’E, fl., fr ., Oct. 1929 ( P!) .

Figures

Fig. 1. — Heliotropium perrieri J.S. Mill.: A, habit; B, adaxial surface of leaf; C, abaxial surface of leaf; D, close up of hairs with evident basal cystoliths on adaxial leaf surface; E, flowering branch tip; F, close-up of flower; G, flower with open corolla; H, pedicel with gynoecium showing united anthers; I, open calyx showing gynoecium with conical stigma; J, whole fruit with persistent calyx, viewed from above; K, fruit enclosed in persistent calyx; L, single nutlet showing dorsal surface. A-L from Perrier de la Bâthie 1369.

Fig. 2. — Distribution of Heliotropium perrieri in Madagascar.