Drosera peltata is an erect tuberous species native to the east coast of Australia. It is the type species of the convoluted and somewhat controversial species complex.
In the past, all erect sundews on the east coast of Australia was considered Drosera peltata. This complex of plants has been subject to various reviews, which define varying numbers of taxa. (For a good review, refer to the ICPS article). As I understand it, Drosera auriculata and lunata are uncontroversially separated on the basis of their glabrous sepals. Drosera hookeri and gunniana form a separate complex of plants with strong basal rosettes and bottle shaped seeds. Drosera yilgarnensis is considered a Western Australian relative.
A contention lies in the distinction between Drosera peltata and gracilis. Drosera peltata was originally described from plants in the Sydney region by Thunberg in 1797. These plants are therefore Drosera peltata in the strict sense. Some authors consider that the type specimen for Drosera gracilis (from Arthur’s Lake in Tasmania) are identical to the Sydney plants and so consider Drosera gracilis to be a subspecies of Drosera peltata. Others make a distinction, mostly based on seed morphology, coloration and stature.
Drosera peltata, as originally described, grows in heathy sandstone substrates within the Sydney region and surrounds. A basal rosette is sometimes absent or reduced in flowering sized plants. The species has a slender stem and crescent shaped leaves, both usually coloured olive green to bronze in good light. The inflorescence is held with considerable distance between the last set of leaves. The flower buds are well spaced apart. The sepals are somewhat variable but are ovate-elliptical and hairy. The sepal hairs of the plants in Northern Sydney are thick and mostly do not have glands at their tip. The seed is oval in shape, with a sharp point at one extremity and a very small lobed point at the other extremity. The plants are tall, growing over 30 cm and are usually self supporting or lean on surrounding vegetation.
Drosera peltata is distinguished from Drosera gracilis by the shape of the seed (those of D. peltata are rounded and ‘lemon’ shape whereas those of D. gracilis feature a long, tapering appendage at one extremity). D. peltata is also generally taller than D. gracilis (D. peltata usually grows above 30 cm whereas D. gracilis tends to max out at around 20 cm).
Drosera peltata is distinguished from the Drosera hookeri/gunniana complex by the proportions of the plant (D. peltata is unbranched, tall, has an inflorescence with widely spaced flower buds with mature plants usually lacking a basal rosette; D. hookeri is multibranched, short, has an inflorescence with crowded flower buds and a persistent basal rosette; D. gunniana is tall and has crowded flower buds and a persistent basal rosette). The seeds of the D. hookeri/gunniana complex also feature a prominent lobed appendage at the extremity, which is absent in D peltata.
D. peltata is distinguished from Drosera auriculata and D. lunata by its hairy sepals.